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Entries for December 2009

December 31, 2009

Emotional reactions to Darwin

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

There is no doubt that Darwin's ideas about evolution by natural selection carry a huge emotional impact. For many people the idea that "we are descended from apes" is too awful to contemplate and is sufficient reason alone to dismiss any claim that natural selection holds the key to understanding how we came about. (Of course, we are not descended from apes. The more accurate statement is that apes and humans share common ancestors, making them our cousins, but even this refinement does not take away the stigma that supposedly comes with being biologically related to animals such people consider inferior.)

This unease about being biologically linked to other species is widespread and transcends any particular religious tradition. In Sri Lankan rural areas, one would frequently see monkeys on trees by the side of the road. As children when we were passing them, almost invariably someone would point them out and say things like "Your relatives have come to see you." Similarly, if one said that one was going to visit the zoo, this would also result in the question as to whether one was going to visit one's relatives. This kind of humor among children was commonplace, and reflected a reflexive instinct that humans were superior to all other animal forms, and reinforced the belief that some sort of special creative process must have been at work to produce us.

But if the thought of being related to apes gives some people the creeps, imagine how much worse it will for them to realize that as we go farther back in evolutionary time, we are cousins to all sorts of life forms that might make people even more squeamish.

Reading Richard Dawkin's book The Ancestor's Tale (2004) I found that I myself was not immune from that kind of emotional reaction, even though I have no problems intellectually with accepting natural selection and all its consequences.

For example, I had little difficulty emotionally accepting that the apes and monkeys are my cousins, partly because, I suppose, that idea has been around for a long time and I have simply got used to it. Also a common ancestor to the humans and apes would not look very different from us now and is easier to envisage. But as the evolutionary clock went back in time, and I started imagining what my deep ancestors looked like, I had a variety of reactions.

The idea that I had common ancestors with dogs and cats and horses (those evolutionary branches separated from the human branch at about 85 million years ago (Mya)) did not cause me any problems. I kind of liked the idea that my dog Baxter and I can trace our separate lineages back to a time when we both had a common ancestor. It is clear that our common ancestor would not look much like present-day humans or dogs, but I cannot imagine what it might have looked like apart from having some of the common characteristics shared by dogs and humans, like being four-limbed, warm-blooded, invertebrates.

More annoying was the realization that the branch that led to the rodents like rats, squirrels and rabbits only separated from the human branch at 75 Mya, meaning that those animals that we consider vermin and would not think of having in our houses, actually have a closer relationship to humans (since our common ancestors lived more recently) than those whom we love and welcome into our homes as pets, like dogs and cats.

Somehow, the emotional reaction of finding oneself having common ancestors with dignified and majestic animals like whales (85 Mya) and elephants (105 Mya) is positive while being linked to things like snakes (at 305 Mya) felt kind of icky.

A hard bridge to cross (again I mean emotionally) was accepting that frogs and toads and salamanders shared a common ancestor with me at about 340 Mya, perhaps because I share the common perception that these animals are slimy.

Going back further, I had little negative emotional reaction to realizing that I had a common ancestor with sharks at 460 Mya but the thought that flatworms and I were related at 630 Mya was harder to take. I suppose that this is because sharks are usually perceived as admirable and graceful (if dangerous) animals while I have never liked worms, seeing them as somehow disgusting. Perhaps I will now have warmer feeling towards them, seeing that we are relatives.

Once I got over the emotional hurdle of being able to accept the fact that worms and I have common ancestors, the rest was pretty easy to accept, perhaps because the earlier life forms that our common ancestors took had to be so different that I could not really relate to them (let alone imagine them) in any way. Thus it was a breeze to accept that I am related (however distantly) with sponges, bread moulds, amoeba, and bacteria.

It was amusing to keep monitoring my emotional reactions as I read about the backward evolutionary journey. But like most difficult journeys, taking that first step is the hardest. And now I have a better understanding why many religious people simply cannot take that first step and acknowledge that chimpanzees are our cousins, in fact are the closest cousins we have in the animal kingdom, with our common ancestor living just 6 million years ago. Because once you accept that, then you have embarked on journey whose inevitable end is that you end up as one with a bacterium. It is hard to think of you being created in god's image after that.

Thus I am somewhat sympathetic to those people who find Darwin's ideas hard to stomach and desperately seek to find a more palatable alternative. However, I think their task will prove hopeless, since the basic tenets of evolution are here to stay and so we may as well get used to it.

December 30, 2009

Looking for deep ancestors

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

Richard Dawkins in his book The Ancestor's Tale (2004) tells a fascinating story. He models his book on a journey that, rather than moving through space to a particular destination, is moving in the temporal dimension, going steadily back in time. He calls it a "pilgrimage to the dawn of evolution." He starts with present day humans and follows them back into history. One reason he gives for going back in time instead of starting at the beginning and going forwards as is more commonly done is to avoid a common trap of perception. When you tell the story forwards, it is hard to avoid giving the impression that life evolved purposefully, that human beings were somehow destined to be. This is counter to evolutionary theory that says that evolution is not directed towards any goal. It tells us how the present emerged from the past. It does not tell us how the future will emerge from the present.

Dawkins points out that the another advantage of telling the story backwards is that you can choose any of the current species and go back in time and tell pretty much the same story.

As I have mentioned earlier, we quickly (in just 2,000 years) reach the time when the most recent common ancestor lived and soon after that (about 5,000 years ago) reach a point when all our ancestors were identical.

But this convergence of ancestry is not just for humans, it is for all species. If we go far enough back in time, even my dog Baxter and I share the same ancestor, which I find a very appealing notion.

Anyway, here is a concise summary of the landmarks on this pilgrimage back in time, along with some other landmarks.

About 10,000 years ago, the agricultural revolution began and about 12,000 years ago saw the beginnings of language. About 160,000 years ago saw the beginning of what we would consider modern humans, and beyond that we start reaching the precursors to modern humans, a famous milestone being the fossil Lucy, dated to 3.2 Mya (million years ago).

As we go further back in time in this pilgrimage, other species start 'joining us' in our journey. What this means is that we reach times at which an earlier species existed which then split into two branches and diverged evolutionarily to what we see now. So if we go back further in time, we should cease to view the pilgrims on the journey as a combined group of humans and other species but instead see the travelers as that earlier common ancestor species. He calls these common ancestors 'concestors'. (Concestor 0 in Dawkins' scheme is the most recent common ancestor of all humans (or MRCA) that I have discussed earlier and who lived just a few thousand years ago.)

Going back in time, at 6 Mya we meet concestor 1 when we join up with the ancestors of chimpanzees. As we go even back further, we (and when I say 'we', I remind you that we should not think of 'us' as humans at this point but as the common ancestor species of humans and chimpanzees) join up at about 40 Mya successively with gorillas, orang utans, gibbons, and finally monkeys. Remember that the 'pilgrims' look different as we pass each concestor point.

Concestor 8 occurs at about 63 Mya when we join up with mammals like lemurs and lorises. (Just prior to this, around 65 Mya, was when all the dinosaurs went extinct.) As you can imagine, concestor 8 would not look much like present-day humans at all.

About 75 Mya, we join up with rats, rabbits and other rodents (concestor 10), at 85 Mya with cats and dogs (concestor 11), at 105 Mya with elephants and manatees (concestor 13), at 310 Mya with snakes and chickens (concestor 16).

At 340 Mya, we make a big transition when join up with the ancestors of amphibians, such as frogs and salamanders (concestor 17). This point marks the first time that animals moved out of the water.

Around 440 Mya we join up with various kinds of fish (concestor 20), and around 630 Mya with flatworms (concestor 27).

After various other species ancestors' join ours, the next big rendezvous occurs at about 1,100 Mya when we join up with the ancestors of fungi, such bread molds and truffles (concestor 34).

Some time earlier than that (passing the connection with amoeba at concestor 35) but before 1,300 Mya (it is hard to pin the date) is when the next major transition occurs when we join up with green plants and algae. This common ancestor is concestor 36.

At about 2,000Mya we arrive at concestor 38 where every species is now represented by a eukaryotic (nucleated) cell.

At about 3,500 Mya we meet up with our earliest ancestors, the eubacteria (concestor 39), the original form of life.

Dawkins' reverse story can be seen visually, told in a beer commercial in 50 seconds flat to the pounding beat of Sammy Davis Jr. singing The Rhythm of Life. (A minor quibble: There is one way in which this fun visual representation is not accurate. It shows three humans going back in evolution until we join up with ancestors of the present-day amphibians (concestor 17) in identical parallel paths. This is ruled out by the reductio ad absurdum argument written about earlier, where it was established that all present day humans must have had a single common ancestor in any earlier species.)

I must say that this book was an exhilarating journey. To see the whole of the evolution of life going backwards and merging together was a nice new way of seeing the process. Those of you who are interested in the grand sweep of evolution written for a non-specialist will find Dawkins' book a great resource.

POST SCRIPT: The Boxer

A live performance of Simon and Garfunkel singing one of my all-time favorite songs The Boxer.

December 29, 2009

Sexual selection

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

In a previous post, I discussed the fact that although all of us have the identical set of ancestors who lived just 5,000 years ago, this does not mean that we have the same genes. The fact that we are different is due to the fact that if most of the mating occurs within a group, then this can result in certain features becoming emphasized. In extreme case, this initial isolated mating pattern can result in a new species being formed that cannot mate with other groups that it could have done in the past.

I had always thought that the two organisms belonged to different species if they were biologically different enough that they either could not produce offspring or, as in the case of mules produced by horses and donkeys, the offspring were infertile and thus not able to reproduce.

But I learned from Richard Dawkins' book The Ancestor's Tale (2004) that two things can be considered different species even if they are perfectly capable of producing fertile offspring. All that is required for them to be considered to be different species is that they are not found to mate in the wild for whatever reason.

Normally, this happens when there is some kind of barrier that separates two groups of the same species so that they cannot mate. "No longer able to interbreed, the two populations drift apart, or are pushed apart by natural selection in different evolutionary directions" (p. 339) and thus over time evolve into different species. But the separation can also occur due to sexual selection.

He gives a fascinating example of this on page 339. He describes experiments done with two species of cichlid fish. The two species live together in Lake Victoria in Africa and are very similar, except that one has a reddish color and the other bluish. Under normal conditions, females choose males of the same color. In other words, there was no hybridization between the two colors in the wild, thus meeting the requirements for being considered different species. But when experimenters lit the fish in artificial monochromatic light so that they all looked dirty brown, the females no longer discriminated among the males and mated equally with both kinds of males and the offspring of these hybrids were fully fertile.

He also describes ring speciation using the example of the herring gull and lesser black-backed gull (p. 302). In Britain, these two kinds of birds don't hybridize even though they meet and even breed alongside one another in mixed colonies. Thus they are considered different species.

But he goes on to say:

If you follow the population of herring gulls westward to North America, then on around the world across Siberia and back to Europe again, you notice a curious fact. The 'herring gulls', as you move around the pole, gradually become less and less like herring gulls and more and more like lesser black-backed gulls, until it turns out that our Western European lesser black-backed gulls actually are the other end of a ring-shaped continuum which started with herring gulls. At every stage around the ring, the birds are sufficiently similar to their immediate neighbors in the ring to interbreed with them. Until, that is, the ends of the continuum are reached, and the ring bites itself in the tail. The herring gull and the lesser black-backed gull in Europe never interbreed, although they are linked by a continuous series of interbreeding colleagues all the way around the other side of the world.

Dawkins gives a similar example of this kind of ring speciation with salamanders in the Central Valley of California.

Why is this interesting? Because it addresses a point that sometimes comes up with skeptics of evolution. They try and argue that there is a contradiction if we had evolved from an ancestor species that was so different from us that we could not interbreed with that species. Surely, the argument goes, doesn't speciation imply that if species A evolves into species B, then must there be a time when the child is of species B while the parent is of species A. And isn't that a ridiculous notion?

The herring gulls and salamanders are the counterexamples in space (which we can directly see now) of the counterargument in time (which we can only infer). What it says is that as descendants are produced, they form a continuum in time. Each generation, while differing slightly, can interbreed with its previous generation, but over a long enough period of time, the two end points of the time continuum need not be able to interbreed.

Thus it is possible for an organism to be intermediate between two species.

Coming back to the question of why we look so different if we all shared common ancestors so recently, it is likely that the kind of selectivity practiced by the cichlid fish has resulted in certain features being shared by groups that interbreed within a restricted domain bounded by distance and geography and culture, although the process has not become so extreme that we have formed into distinct species.

I apologize for boring those readers who had had a much more extensive biology education than I have because all these things which I have been writing about recently on evolution must be well known to them. But I find all this perfectly fascinating and novel.

December 28, 2009

Why we look different despite having identical ancestors

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

In the previous post in this series, I reported on a paper by Douglas L. T. Rohde, Steve Olson, and Joseph T. Chang and published in the journal Nature that said that if we go back about 5,000 years, the ancestors of everyone on Earth today are exactly the same. This date is called the IA point, where IA stands for 'identical ancestors'.

One question that will immediately arise in people's minds is that if all our identical ancestors lived so recently, how is it that we look so different? If you take four people from China, Sri Lanka, Sweden, and Malawi, they are usually fairly easily distinguishable based on physical appearance alone, using features such as skin color, hair, facial features, etc. How could this happen if they all had identical ancestors as recently as 5,000 years ago?

The answer lies in the fact that while it is true that we all share the same ancestors, it does not mean that we all received that same genetic information from that common ancestral pool.

It is true that each of us gets exactly half our genes from our fathers and half from our mothers. But when we pass on our genes to our children, while each child gets exactly half from each parent, that does not imply that they get exactly one quarter from each grandparent. What is true is that on average each child gets one quarter of the genes from each grandparent.

The reason for this is because when a sperm or egg is formed, the genetic information (say in the egg formed in the mother) that goes into it undergoes a process of recombination in which the genes the mother obtained from her parents get mixed up before the transfer into the egg. It is thus theoretically possible, though unlikely, that a child will have zero genetic information from one of her four grandparents.

Furthermore, as we go down to the next generation, the average genetic information received by a child is now just one-eighth from any given great-grandparent. After many generations, even the average contribution of someone to each descendant approaches zero and it is not hard to imagine that some ancestors will have descendants who inherited none of their genetic information. In fact, as Rohde, Olson, and Chang say, "because DNA is inherited in relatively large segments from ancestors, an individual will receive little or no actual genetic inheritance from the vast majority of the ancestors living at the IA point."

Furthermore, "In generations sufficiently far removed from the present, some ancestors appear much more often than do others on any current individual’s family tree, and can therefore be expected to contribute proportionately more to his or her genetic inheritance. For example, a present-day Norwegian generally owes the majority of his or her ancestry to people living in northern Europe at the IA point, and a very small portion to people living throughout the rest of the world."

So even though we all have the same set of ancestors, the amount of genetic information received from any one ancestor will vary wildly from person to person.

As long as populations remained largely isolated, they could thus evolve different physical characteristics, although even a tiny amount of migration between populations is enough to create the early common dates of the MRCA (most recent common ancestor) and IA.

There are some factors that could shift those dates back further.

If a group of humans were completely isolated, then no mixing could occur between that group and others, and the MRCA would have to have lived before the start of the isolation. A more recent MRCA would not arise until the groups were once again well integrated. In the case of Tasmania, which may have been completely isolated from mainland Australia between the flooding of the Bass Strait, 9,000–12,000 years ago, and the European colonization of the island, starting in 1803, the IA date for all living humans must fall before the start of isolation. However, the MRCA date would be unaffected, because today there are no remaining native Tasmanians without some European or mainland Australian ancestry.

No large group is known to have maintained complete reproductive isolation for extended periods.

It seems to me that these results arguing for the fact that our most recent common ancestor lived about 2,000 years ago and that we all have the same common ancestors who lived just 5,000 years ago are pretty robust.

This has profound implications for origins myths and tribalism. Some people like to have a sense of racial pride by thinking that they represent 'pure' races. This research argues that this view is rubbish. None of us are 'pure'. We are all cousins with every other person on the planet.

December 25, 2009

Reason's Greetings!

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

Baxter and I would like to wish all the readers of this blog our best wishes for the season. May all of you find peace and happiness.

We live in a world divided by conflicts based on religion, ethnicity, and nationality. But all these divisions are of human creation that merely serve to set groups of people up against each other by encouraging appeals to tribal loyalties. They have at best merely superficial meaning, and all came into being within the last four thousand years or so, a mere instant in the vastness of time that life and the universe have existed.

Contrast the divisiveness of religion, ethnicity, and nationality with the unifying effects of science in general and evolution in particular. If everyone were to accept the truth of evolution, that each one of is connected to every other living organism that lives now and has ever lived by the Darwinian tree of life, perhaps we can overcome tribal feelings and move towards a truly just and peaceful world.

We are fortunate that we are alive to experience life in its gloriousness. We should strive to enable everyone to experience that life to its fullest, free from want, and with the basic needs of food, shelter, clothing, education, and medical needs met. We can do that it we do not waste so much time and energy and resources on parochial interests at the expense of the general good.

So let's spread that message.

baxtertree.JPG

December 24, 2009

More realistic calculation of the date of our most recent common ancestor

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

In the previous post, I discussed the calculation of Joseph T. Chang in which he showed that the most recent common ancestor (MRCA) of all the people living today lived around 1100 CE, while around 400 CE everyone who lived then was either the ancestor of all of us or none of us. The date when this occurs is called the IA (identical ancestor) date.

Chang got these results assuming that the population is constant over time at some value N, that the generations (with each generation lasting 30 years) are discrete and non-overlapping (i.e. mating took place only between males and females of the same generation), and that mating was random (i.e., there was equal probability of any one male in a generation to breed with any female of that same generation.)

What happens to these dates if you relax these unrealistic assumptions? One practical difficulty of going to more realistic models is that exact mathematical calculations become impossible and one has to resort to computer simulations. This was done by Douglas L. T. Rohde, Steve Olson, and Joseph T. Chang and their results were published in the journal Nature (vol. 431, September 30, 2004, pages 562-566).

As a first improvement, they divided the world into ten population centers (or 'nodes'): one each in North America, South America, Greenland, Australia, the Pacific Islands, and the Indonesian archipelago, and two nodes in Africa and in Asia. Within each subpopulation, they assumed random mating, but allowed for neighboring populations to exchange just one pair of migrants per generation. Their computer models found that the best way to accommodate varying populations was to take a fixed value N equal to the population at the time of the MRCA. They assumed N to be 250 million, which was approximately the global population in the year I CE.

Using this more realistic model, and a generation span of 30 years, they obtained the MRCA date as 300 BC and the IA date as about 3,000 BCE, both still surprisingly recent.

They then constructed an even more sophisticated and realistic model. They broke up the inhabited area into three levels of substructure: continents, countries, and towns. (These were not real places, of course, just models, but they used our knowledge of geography and migrations routes that existed before 1,500 CE to create their models.)

The model allowed for each person to have a single opportunity to migrate from his or her town of birth. Within a country, they could migrate to any other town. If the migrants went to another country, the probability of that occurring decreased with the distance to the new country. To go to another continent required them to go through certain ports, and so on. The model also incorporated our knowledge of the size of ports and when they opened up.

Generations could also overlap in this model and the birth rate of each continent was adjusted to match historical estimates.

After making all these sophisticated adjustments to make their model more realistic, they arrived at what they felt was a reasonable estimate for the MRCA and IA dates. It turns out that the MRCA lived around 55 CE and the IA date is about 2,000 BCE. They also found that our most recent common ancestor probably lived in eastern Asia, not Africa as had been commonly supposed.

So despite going to considerable lengths to simulate a realistic pattern of population growth, mating, and migration, the dates arrived at for the MRCA and the IA are still surprisingly recent.

(If the authors of the paper made their parameters very conservative, they pushed the date for the MRCA only as far back to 1,415 BCE and the IA date to 5,353 BCE.)

A little reflection should persuade anyone that this result that our most recent common ancestor lived as late as 55 CE and in just 2,000 BCE we had identical ancestors has profound implications for the way we view ourselves and our relationship with others. The authors capture the wonder of it all when they end their paper with the following comment:

[O]ur findings suggest a remarkable proposition: no matter the languages we speak or the colour of our skin, we share ancestors who planted rice on the banks of the Yangtze, who first domesticated horses on the steppes of the Ukraine, who hunted giant sloths in the forests of North and South America, and who laboured to build the Great Pyramid of Khufu.

I find this amazing and remarkably encouraging. It should be more widely known. If more people realized how close we are to each other, perhaps we would stop killing one another and treat each other like the fairly close relatives we truly are.

POST SCRIPT: Is that the real reason for the season?

Stephen Fry tells us about this Roman god named Mithras whose life story shows a remarkable resemblance to that of Jesus. What a coincidence!

December 23, 2009

The most recent common ancestor of all humans living today

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

In order to find the date of the most recent common ancestor (MRCA) of all the people living today, Chang started out by constructing a simple mathematical model of population mixing. (See

He assumed that the population is constant over time at some value N. He assumed that the generations are discrete and non-overlapping (i.e. mating took place only between males and females of the same generation). He also assumed that mating was random. In words, that there was equal probability of any one male in a generation to breed with any female of that same generation.

Of course, none of these assumptions is realistic. The size of a population changes with time for a variety of reasons. People also do not mate at random, being more likely to choose from those nearby, and from people within their same groupings whether those be economic, social, cultural, class, religion, etc. And cross-generational matings are not uncommon.

But for the purposes of mathematical simplicity, and to get a rough idea of the timescales involved, Chang's simple model is worth looking at because it enables him to do a rigorous mathematical calculation for the date of the MRCA. What Chang found, to everyone's surprise, was that the date of existence of the MRCA of all the humans living today was very recent. He found that the number of generations that one has to go back to get an MRCA was log2N, which stands for the logarithm to base 2 of the population size N. He further found that even though this was a statistical calculation, the result was very sharply peaked about this value, meaning that it was highly unlikely that the MRCA date would differ by even 1% from this value.

If you take a population N of size one million, the number of generations you have to go back to get to our MRCA is only 20. If you take a population of one billion, our MRCA existed about 30 generations ago, or around 1100 CE (for an average generation span of 30 years).

So according to Chang's model, our MCRA lived far more recently than anyone had imagined, and way more recently than Mitochondrial Eve (~140,000 years ago) or Homo erectus (~250,000 to one million years ago). It is fascinating to think that every single one of us living today share at least one ancestor who was living in the Middle Ages. I have been wondering who that person was, and where he or she lived, and what he or she was like.

But that was not the only surprising thing that Chang found. Once you get an MRCA, then that person's parents are also common ancestors for all of us, as are his/her grandparents and great-grandparents, and so on. In fact, just as the number of our ancestors increase rapidly as we go back generations, so do the number of our common ancestors once we go further back than our MRCA.

Chang found that if you go far enough back, you reach a point when every single person living at that time is either the ancestor of all of us or none of us (i.e., that person's line went extinct). In other words, there is no one who lived at that time who is the ancestor of just some of us. It is an all-or-nothing situation with an 80% chance of the former and 20% chance of the latter. To be perfectly clear about this (because it is an important point), at one particular time in the past, 20% of the people who lived at that time have no descendants alive today. Each one of the remaining 80% of the people has the entire world's population today as descendants.

So all of us have the identical entire set of ancestors who lived at that time. Chang calls that time the IA (standing for 'identical ancestors') time.

Using the same assumptions as before, Chang's calculations for the number of generations to reach the IA date is 1.77log2N. For a billion people, it amounts to about 53 generations ago. This works out to 675 CE for a generation span of 25 years and 410 CE for 30 years.

It seems amazing (to me at least) that all of us living right now have identical ancestors that lived so recently, roughly around the period when the Prophet Muhammad lived (570-632 BCE). In fact Mark Humphrys, a professor of computer science at Dublin City University in Ireland using a different technique estimates that Muhammad, the founder of Islam, appears on the family tree of every person in the Western world. (Thanks to commenter Steve Lubot for this link.) But it is important to realize that there is nothing special about Muhammad or about the Western world.

So taking Chang's results at face value, all the people who fight over religion today are highly likely to be descendants of each and every religious leader who lived from the time of the Prophet Mohammed and earlier. So in a very real sense, they are killing their own cousins.

Of course, Chang's results were based on a highly simplified mathematical model. In the next posting in this series, we'll see what happens when we create more realistic scenarios of population changes and mating patterns.

POST SCRIPT: File under things I don't understand

What is the book most often stolen by shoplifters at bookstores? The Bible.

The article also seems to suggest that shoplifting is a routine activity among young people of all social classes in the US, almost a rite of passage. Could this be true?

December 22, 2009

Some surprising facts about ancestors

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

In 1999, Joseph T. Chang published a very interesting paper in the journal Advances in Applied Probability (vol. 31, pages 1002-1026) titled Recent Common Ancestors of all Present-Day Individuals. To understand the paper, it helps to reflect a little on the mathematics of genealogy.

One rock-solid fact of ancestry is that every person has two, and only two, biological parents. They in turn each have two parents so going back two generations gives a person four ancestors. If you go back three generations, you have eight ancestors and so on. Each generation that you go back doubles the number of ancestors in the previous generation.

We all know that this kind of geometric progression results in one reaching very large numbers very soon and by thirty generations, the number of ancestors one has acquired has ballooned to over one billion. In forty generations, we have over one trillion ancestors.

Conservatively allowing for each generation to span 30 years (which is a little large), going back thirty generations takes us back to about 1100 CE where the population was only about 300 million, and forty generations takes us back to 800 CE where the population was less than 200 million. (If we take each generation as averaging 25 years, 30 generations takes us back to 1250 CE when the population was 350 million and in forty generations we reach 1000 CE where the population was 200 million.)

Having more ancestors that the total population leads to the clear conclusion (which is not that surprising once one thinks about it) that all our ancestors cannot have been distinct individuals but were shared. In other words, my great-great-great-grandfather on my father's side had to be the same person as my great-great-grandfather on my mother's side, or something like that.

But the interesting point is that each one of us has over a trillion ancestors in just forty generations, which must mean that you, the reader, and I must have some shared ancestors as recently as a thousand years ago, unless the huge population of your ancestors were entirely isolated from the huge population of my ancestors, with no mixing at all between them. Given the large numbers of ancestors involved, this kind of isolation seems highly unlikely unless there was some major geographical barrier separating the populations. We know that this is not the case, since by 1000 CE people were able to travel pretty much all over the inhabited world, and all you need is just one person from my group of ancestors mating with one person from your group of ancestors to break the isolation, because then all the ancestors of that pair are shared by both of us.

So if you and I (as just two people) share common ancestors, then we can see that if we go back far enough in time, all of us living on the world today should share at least some common ancestors. One question that Chang was investigating was that of finding out, from among all the common ancestors, when the most recent common ancestor (MRCA) of all the people living in the world today lived.

The concept of the MRCA is interesting. My siblings and I share all our ancestors so the MRCA is not meaningful. The MRCA of my first cousins and I are the one set of grandparents that we have in common. As my cousins get more distant, the MRCA goes back in time but it is not hard to see that an MRCA must exist for those whom we commonly refer to as 'blood' relatives.

For those who take the Bible literally, definite common ancestors would be Noah and his wife. Since everyone except the two of them and their sons and their sons' wives were killed by god in the flood, all the current inhabitants of the world should have Noah and his wife as common ancestors. But they may not be the MRCA because their sons' descendants may also have intermarried, creating a more recent MRCA.

For those of us who accept evolution, it is not hard to get our minds around the concept of all of us having an MRCA, and the fact that we must have a shared ancestor in an earlier species has a rigorous proof (see the previous post) and is fairly easily accepted. What people thought was that this person probably existed around the time of our ancestor Homo erectus, perhaps a million years ago.

But when analysis was done on the mitochondrial DNA, and its mutation rate was used to triangulate back to the time when all the current mitochondrial DNA converged on a single individual, people were surprised that the calculations revealed that the MRCA deduced from this analysis, (nicknamed Mitochondrial Eve) lived much more recently, only about 140,000 years ago, probably in Africa. All present-day mitochondrial DNA is descended from this single individual. A similar analysis can be done for the Y chromosome to trace back to 'Y-chromosome Adam', and that person lived about 60,000 years ago (Richard Dawkins, The Ancestor's Tale (2004), pages 52-55).

But as Dawkins cautions (page 54):

[I]t is important to understand that Eve and Adam are only two out of a multitude of MRCAs that we could reach if we traced our way back through different lines. They are the special-case common ancestors that we reach if we travel up the family tree from mother to mother to mother, or father to father to father respectively. But there are many, many other ways of going up the family tree: mother to father to father to mother, mother to mother to father to father, and so forth. Each of these pathways will have a different MRCA.

Our normal concept of genealogy traces back through both sexes and thus the web of ancestral pathways becomes increases tangled and complex as you go back in time. As a result there is a greater chance of my ancestral pathways intersecting with the ancestral pathways of other people. It is thus reasonable to suppose that if we look at all these pathways, we will find a more recent MRCA than Mitochondrial Eve or Y-chromosome Adam. But this kind of calculation using mutation rates is not easy to do for things other than sex-specific chromosomes like mitochondrial DNA.

In order to try and fix the date of existence of the MRCA of everyone living today using the lines through both sexes, Chang used the tools of mathematics and statistics rather than genealogical charts or DNA mutations. And he found something very surprising, to be discussed in the next posting.

POST SCRIPT: Praying for defeat of health care

Congressperson Michele Bachmann (R-Loony) leads a group of people in a creepy prayer. Watch Tony Perkins, head of the Family Research Council that organized the event, drink some coffee in the middle of the prayer. You shouldn't have done that, Tony. Jesus just hates it when people eat and drink when they should be groveling before him. Actually, Tony seems to show a remarkable lack of enthusiasm, not standing up and holding hands at the end.

If the health care legislation is defeated, they will no doubt attribute it to their prayers. But what if the health care bill that they are earnestly praying against actually passes, what will they conclude? That god wanted it to pass? Nah. That god was playing golf at that time and so missed their prayer? Nah. That god wanted to punish Tony Perkins for drinking coffee during the prayer? Nah.

Like all religious people when their prayers are never answered, they will ignore the issue (since no one usually asks them because the faith of religious must not be disturbed) or they will say that god agrees with them (isn't it amazing that god agrees with every religious person?) but that he has a cunning plan that we cannot fathom.

It is all so predictable.

December 21, 2009

Our common ancestors

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

Darwin's theory of natural selection implies that we are all descended from common ancestors. Most people who have doubts about the theory tend to think that this is a proposition that we can either choose to accept or deny. After all, no one was around to see it, were they?

But Richard Dawkins' excellent book The Ancestor's Tale (2004) gives a surprisingly rigorous argument (on page 39) that back in the distant past, we must have all had common ancestors. He is such a good writer, both stylish and concise, that paraphrasing him would be a waste of time and I will give you an extended quote:

If we go sufficiently far back, everybody's ancestors are shared. All your ancestors are mine, whoever you are, and all mine are yours. Not just approximately, but literally. This is one of those truths that turns out, on reflection, to need no new evidence. We prove it by pure reason, using the mathematician's trick of reductio ad absurdum. Take our imaginary time machine absurdly far back, say 100 million years, to an age when our ancestors resembled shrews or possums. Somewhere in the world at that ancient date, at least one of my personal ancestors must have been living, or I wouldn't be here. Let us call this particular little mammal Henry (it happens to be a family name). We seek to prove that if Henry is my ancestor he must be yours too. Imagine, for a moment, the contrary: I am descended from Henry and you are not. For this to be so, your lineage and mine would have to have marched, side by side yet never touching, through 100 million years of evolution to the present, never interbreeding yet ending up at the same evolutionary destination – so alike that your relatives are still capable of interbreeding with mine. This reductio is clearly absurd. If Henry is my ancestor, he must be yours too. If not mine, he cannot be yours.

Without specifying how ancient is 'sufficiently', we have just proved that a sufficiently ancient individual with any human descendants at all must be an ancestor of the entire human race. Long-distance ancestry, of a particular group of descendants such as the human species, is an all-or-nothing affair. Moreover, it is perfectly possible that Henry is my ancestor (and necessarily yours, given that you are human enough to be reading this book) while his brother Eric is the ancestor of, say, all the surviving aadvarks. Not only is it possible. It is a remarkable fact that there must be a moment in history when there were two animals in the same species, one of whom became the ancestor of all humans and no aardvarks, while the other became the ancestor of all aardvarks and no humans. They may well have met, and may even have been brothers. You can cross out aardvark and substitute any other modern species you like, and the statement must still be true. Think it through, and you will find that it follows from the fact that all species are cousins of one another. Bear in mind when you do so that the 'ancestor of all aardvarks' will also be the ancestor of lots of very different things beside aardvarks[.]

There is one aspect of this argument that is crucial and that is that our common shared ancestor Henry that Dawkins is talking about has to have lived at a time when he was of a different species from us, since the reductio argument he is using depends crucially on the unlikelihood of species evolution following separate but parallel tracks to arrive at the same species end point. Since all humans are descendants of this single animal Henry, we conclude that all the early humans must be the ancestors of all of us. So when Dawkins talks of us all sharing the same ancestors at some point, he means human ancestors, since all humans evolved from Henry's line.

Of course, as time progresses, the human species descended fro Henry produced more descendants who then produced yet more descendants and so on, and there must come a time when the lines diverged so that not everyone living at later times is the ancestor of all of us, but only some. That transition time is called the identical ancestors (IA) time. i.e., Earlier than that, every human was the ancestor of all of us or none of us (i.e., their line went extinct). After the IA time, people share only some ancestors.

It is not hard to see that as time progresses even further, there will come a time when we all share just one common human ancestor, referred to as the most recent common ancestor or MRCA. After that time, everyone living today no longer shares a common ancestor.

I don't know about you, but to me there is something extraordinarily beautiful about this idea that at one point in time we all shared the same single ancestor, and that some time further back, everyone who lived at that time was either the ancestor of all of us or of none of us. It seems to be such a decisive argument against tribalism. It is hard to maintain the idea that some groups of people are 'special' in some way, when we not only all descended from a single animal Henry, but that at a later time we all shared the same set of human ancestors. Not only that, but we are also cousins of all the species that currently exist.

No wonder some religious extremists are afraid to have their children learn the theory of evolution. It is so captivating one can see how it would fascinate and draw in anybody who begins to think seriously about it.

Having established that we have both an MRCA and a time where all our human ancestors were identical (the IA time), this raises the question of when these dates occurred.

And therein lies another surprise, to be discussed in an upcoming post in this series.

POST SCRIPT: Best Christmas film

Forget It's a Wonderful Life. See The Ref (1994) with Denis Leary, Judy Davis and Kevin Spacey. The language is too strong for children but it is hilarious.

I couldn't find a clip from the film but here is Leary doing a Christmas TV program (language advisory).

December 18, 2009

The age of the Earth-12: The final synthesis

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

The minimum age of the Earth kept getting pushed back as older rocks kept being found and methods of analysis improved with the invention of new instruments such as the mass spectrometer. The minimum age was raised to 1.90 billion years in 1935, 3.35 billion years in 1947, to 3.45 billion years in 1956.

But there arose a new problem. Astronomers had discovered that the universe was expanding and Edwin Hubble's (1889-1953) discovery of the law now associated with his name enabled scientists to estimate the time when the universe would have begun, and they initially arrived at an age of 1.80 billion years (Jackson, p. 251). It was absurd to suppose that the universe was younger than the Earth and this caused some consternation. But as the reach of telescopes increased and greater and greater expanses of the vastness of the universe came under observation, the calculated age of the universe kept increasing, to 10 billion years by the early 1950s, to 13 billion years by 1958, and finally to the present value of 13.7 billion years. Thus the potential paradox of the universe being younger than the Earth was resolved.

To obtain the age of the Earth we would need to find rocks that were formed at the time of the Earth's formation. But the problem with finding those rocks is that plate tectonics would likely have crushed most of them and so they are not easy to obtain. Despite this, determined efforts have steadily unearthed older and older rocks. According to the US Geological Survey:

The oldest rocks on Earth found so far are the Acasta Gneisses in northwestern Canada near Great Slave Lake (4.03 Ga) and the Isua Supracrustal rocks in West Greenland (3.7 to 3.8 Ga), but well-studied rocks nearly as old are also found in the Minnesota River Valley and northern Michigan (3.5-3.7 billion years), in Swaziland (3.4-3.5 billion years), and in Western Australia (3.4-3.6 billion years)… In Western Australia, single zircon crystals found in younger sedimentary rocks have radiometric ages of as much as 4.3 billion years, making these tiny crystals the oldest materials to be found on Earth so far. The source rocks for these zircon crystals have not yet been found.

The final major shift in the age of the Earth came when Clair Patterson (1922-1995) studied the age of meteorites that had crashed to the Earth. It was assumed that these meteorites were formed at the same time as the Earth and the solar system but since they arrived here much later were less likely to be contaminated by the ebbs and flows of Earth's geological history. Patterson studied two samples from the Canyon Diablo meteorite that fell in Arizona about 50,000 years ago and reported in 1953 that their ages were 4.510 and 4.570 billion years. More and more meteorites from all over the globe started to be analyzed and the ages were all consistent and converged to 4.550 billion years. The oldest moon rocks have been measured to be between 4.4 and 4.5 billion years old, which is consistent with the other dates.

So that is where we are today, with the age of the Earth determined to be 4.55 billion years, with an uncertainty of about 1%.

The search for the age of the Earth is truly a remarkable story. There are many lessons that the search can teach us but the one that I want to pick out to end this series of posts is how the desire for consistency among the fields of geology, paleontology, chemistry, physics, biology, and astronomy all played a role. One of the consequences of this search has been the intermeshing of these fields, theories in one being interwoven with theories in the others. It is this interconnectedness that gives strength to the conclusions.

Those people who think the Earth is 6,000 years old are living intellectually in a time before the Enlightenment. It is not simply that the value they have for the age of the earth is wrong, even absurdly so. It is that they think they are living in a time when facts were largely isolated things that could be accepted or rejected individually. This is no longer true. Nowadays a scientific 'fact', although identified with one particular field, is the product of a large network of theories encompassing many fields that were once separate. To get an authoritative answer to the question of the age of the Earth you would probably go first to someone identified as a geologist, but her answer will not be the product of just geological research but of a whole complex of theories that spread far and wide. To reject such a fact without exploring the consequences it has for all the other elements that went into its production is to reject science altogether.

Pierre Duhem, one of the earliest people who spoke about the interconnectedness of science, captured this beautifully in a metaphor comparing how a watchmaker and doctor operate:

People generally think that each one of the hypotheses employed in physics can be taken in isolation, checked by experiment, and then, when many varied tests have established its validity, given a definitive place in the system of physics. In reality, this is not the case. Physics is not a machine which lets itself be taken apart; we cannot try each piece in isolation and, in order to adjust it, wait until its solidity has been carefully checked. Physical science is a system that must be taken as a whole; it is an organism in which one part cannot be made to function except when the parts that are most remote from it are called into play, some more so than others, but all to some degree. If something goes wrong, if some discomfort is felt in the functioning of the organism, the physicist will have to ferret out through its effect on the entire system which organ needs to be remedied or modified without the possibility of isolating this organ and examining it apart. The watchmaker to whom you give a watch that has stopped separates all the wheelworks and examines them one by one until he finds the part that is defective or broken. The doctor to whom a patient appears cannot dissect him in order to establish his diagnosis; he has to guess the seat and cause of the ailment solely by inspecting disorders affecting the whole body. Now, the physicist concerned with remedying a limping theory resembles the doctor and not the watchmaker. (my italics)

Duhem wrote this in 1906 in his book The Aim and Structure of Physical Theory. I do not think it a coincidence that this was the very period when convergence of scientific theories was occurring.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: There's a Jesus on a spring?

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December 17, 2009

The age of the Earth-11: The Earth becomes very old again

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

The discovery of radioactivity and the associated concept of half-lives of elements opened up the possibility of determining the absolute age of rocks. This argument was developed by Bertram Boltwood in the very early 1900s and is the process now referred to as radiometry (Jackson, p. 237). The argument goes like this. Suppose a sample of rock is found to contain 100 grams of a parent radioactive material P and 300 grams of the stable final daughter element D in its radioactive series, and also suppose that the half-life of this decay has been measured to be 10 years. If we assume that the rock initially had only the parent element P and no D, then we can assume that rock sample initially had 400 grams of P, then after 10 years, it had 200 grams of P and 200 grams of D, then after another 10 years, it would have 100 grams of P and 300 grams of D, and so on. Hence the rock must have been formed 20 years ago.

The more general formula for calculating the age of a rock is age=(half-life)xlog2(1+Dnow/Pnow), where Pnow is the measured amount of the parent radioactive element in the sample at the current time and Dnow is the amount of the final stable daughter element.

Of course, nothing is that simple in real life. Apart from all the difficulties in finding and measuring the properties of rocks, an obvious complicating factor is that some of the parent and daughter elements may have escaped or entered the sample, which is a real possibility during the time that the rock was molten before it solidified. The effect of this can be corrected for by the method of isochron dating, which I will not get into here but the link gives a very clear discussion. In addition, if there are many different radioactive series with multiple elements and multiple rocks involved, and their results converge around a single age, that lends further confidence to the result.

Now that the absolute ages of rocks could be determined, that meant that scientists could determine the absolute ages of the various geological layers in the Earth's crust (that were formed by sedimentation) in addition to their relative ages. They did this by measuring the ages of the igneous rocks that were formed by volcanic activity that created molten rocks that cooled and are now buried in those layers. This provides an additional measure of the ages of the fossils that are found in those layers.

Apart from all this valuable information about the absolute ages of geological layers and fossils that were now possible to determine, the race was also on to find the oldest rocks on the planet, because those would set a lower bound on the age of the Earth.

Lord Rayleigh in 1905 found rocks that were 141 million years old and shark's teeth that were 77 million years old. In 1907, Boltwood published the ages of mineral specimens that ranged from 400 million to 2.2 billion years (Jackson, p. 237). Such results would have been unthinkable just ten years earlier. The fact that these figures were now not summarily rejected shows how rapidly views had changed.

These much larger times were not uncritically accepted, however. Oddly, some critics were from the field of geology itself. Those who had got used to developing their theories to accommodate a 100 million year old Earth and had resisted efforts to lower it to 20 million, were now disconcerted by the much larger times that were now being suggested. Critics charged that we could not know that the half-lives of radioactive elements had remained the same through all time. Maybe they used to decay faster in early days, misleading us as to their ages.

But as more research was done, these objections began to disappear, and soon other methods (such as the presence of what are known a pleochroic halos in some materials) led to estimates of ages of rocks that were also in the hundreds of millions of years.

Geologist Arthur Holmes (1890-1965) produced a time scale in 1911 based on the rocks found in various geological strata and produced dates for the Carboniferous (340 million years), Devonian (370 million years) and Silurian (430 million years) eras, values that hold up remarkably well when compared with current values of 360, 416, and 444 million years respectively (Jackson, p. 245). Interestingly, the record for the oldest rocks at that time produced by Holmes were from my country of origin Sri Lanka (then called Ceylon), which were 1.64 billion years old.

It is often pointed out, correctly, that scientists can dogmatically cling on to their theories even in the face of contrary evidence. As Max Planck said, "A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it" (Burchfield, p. 165). The deep reluctance to accept the new paradigm may be restricted to only those scientists who, like Kelvin and the age of the Earth, have invested a lot of their own time and prestige in working with the old paradigm. It is often the case that the scientific community as a whole changes its views faster than individual scientists.

The age of the Earth is a case in point. A little over a decade after the discovery of radioactivity, and just four years after Kelvin died unconvinced that the Earth was more than tens of millions of years old, there was no doubt anymore that the Earth was really and truly old, in the billions of years. It was a momentous change in thinking occurring over a remarkably short time, showing how science goes where the evidence leads even if individual scientists resist the changes.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: The grand old traditions

It's time once again to declare war on Christmas.

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The Blitzkrieg on Grinchitude - Treesus & CHRIST-mas Tree
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December 16, 2009

The age of the Earth-10: The revolutionary impact of the discovery of radioactivity

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

The dawn of the 20th century was an extraordinary time of ferment in science. In the case of physics, in addition to the turmoil over the age of the Earth, there was also the well-known crisis that the newly emerging models of the atom as a tiny positively charged nucleus and orbiting negative charges seemed to contradict the well-established theory of electrodynamics. Another crisis was that the 'luminiferous ether', the material believed to permeate all space and the carrier of light waves, seemed to be extraordinarily successful in evading all attempts at detecting its presence or its properties. In addition, the blackbody radiation spectrum seemed to defy understanding on the basis of what were thought to be well-established laws of mechanics and radiation.

But that same period also produced one major scientific revolution after another. 1900 saw the re-discovery of Mendel's theory of genetics that showed that the heritable qualities we had were stored in our bodies in discrete units that were passed on intact to our progeny, and not blended away on breeding as previously thought, thus removing one major objection to natural selection. The full integration of Mendelian genetics with natural selection into what is now known as the neo-Darwinian synthesis was, however, not fully understood until around 1920, with the full flowering of the field of population genetics.

1900 also saw the introduction by Max Planck (1858-1947) of the quantum hypothesis that seemed to explain the blackbody radiation anomaly. 1905 saw the emergence of Albert Einstein (1879-1955) and his theory of relativity that made the ether redundant and dispensable, thus solving the mystery of why it had seemed so elusive. That year also saw the publication of a second paper by Einstein which contained the result that is now famously written as E=mc2. 1913 saw the introduction by Niels Bohr (1885-1962) of the planetary model of the atom, the first step in resolving the contradictions between the new atomic theory and electrodynamics.

But as far as the age of the Earth was concerned, the major discoveries that impacted it was the discovery of X-rays in 1895, followed rapidly by the discovery of the alpha, beta, and gamma radiation of radioactivity. There began a rush to isolate the elements that produced this extraordinary new radiation and to measure their properties. Marie (1867-1934) and Pierre (1859-1906) Curie were among the leaders of the quest in isolating these elements and soon the list contained actinium, uranium, polonium, thorium, and radium.

The key discovery that had relevance for the age of the Earth was the discovery in 1903 by Pierre Curie that radium emitted prodigiously large amounts of heat. An early calculation that same year showed that a mere 3.6 grams of radium per cubic meter would be sufficient to be the source of energy radiated by the Sun (Burchfield, p. 166). Since radium existed in the Earth, people immediately realized that if this heat did not have its origins in gravitational or mechanical or chemical energy (and it soon became clear that it did not and was instead due to the mass to energy conversion discovered by Einstein.), then this meant that there was a source of constant heat generation that had not been previously taken into account.

Since there was no way to determine how much heat was continually being produced in the deep interiors of the Earth by all the radioactive elements there, the old calculation methods of Kelvin and other physicists, who assumed that all the Earth's heat was created at its formation and that the Earth could subsequently be treated as a strictly cooling body, had to be discarded. Furthermore, since there was no longer any method of determining the absolute age of the Earth, the desire of the geologists and paleontologist and natural selectionists for long ages could be accommodated. Too bad that Darwin did not live to see it.

But while radioactivity completely undermined the older methods for determining the age of the Earth, it at the same time gave birth to a new and far more accurate method.

It was Ernest Rutherford (later Lord Rayleigh, 1871-1937) who, with others, was associated with some of the key conceptual breakthroughs involving radioactivity, such as realizing that during radioactive decay, one element became transformed into another, which in turn was transformed into another, and so on until a stable element was reached, at which point the process stopped. He was the one who discovered that if you take a sample of radioactive material, the time taken for the initial amount of material to decay to half its original value was a fixed amount (known as its 'half-life') that is independent of the amount of material you started with.

So if you started with (say) 160 grams of some radioactive element that had a half-life of (say) 10 days, then after 10 days you would have 80 grams left, then after 20 days (i.e. another 10 days) you would have 40 grams left, after 30 days, you would have 20 grams left, and so on, with corresponding increases in the amount of the products created by the decay. What was to prove highly significant and useful was that each radioactive element had its own signature value of half-life and there was a huge range of half-lives for the different radioactive elements, ranging from fractions of seconds to hundreds of millions, even billions of years.

This discovery proved to be the key to finally unlocking the secret of the age of the Earth.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: The Daily Show on Americans going to Mexico for health care.

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December 15, 2009

The age of the Earth-9: Biologists join the geologists against the physicists

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

In the case of biology, Darwin's theory of natural selection had been in retreat during the latter half of the 19th century under the assaults of both physicists and some biologists. Fleeming Jenkin (a physicist, engineer, and collaborator of Kelvin) had, in a review of Origins, delivered a severe critique of Darwin's theory. He pointed out that not only was the time available insufficient for natural selection to work, but that the then-dominant theory of 'blending inheritance' (which said that children had a mixture of the qualities of their parents) worked against Darwin's theory, since even if one parent experienced an advantageous mutation, that person's child would only have half of it because the other parent would not have it, the grandchild one-fourth, and so on. The mutation would thus get diluted and disappear over time, and not grow and dominate the population, as natural selection argued.

Darwin had in fact already anticipated this difficulty and pre-emptively suggested that if the mutation occurred in several people and they mated with each other, then the dilution of the advantage would not occur and the population could grow. But he knew this was a weak argument. As a result, by 1880 Darwin was yielding somewhat on natural selection, saying that he had never argued that it was the only mechanism at work, which was true. He had always allowed for some Lamarckian influence though he was not fond of the idea. He now started giving greater room for Lamarckian mechanisms than he had done in the past.

But he was still hopeful that natural selection would eventually weather the storm caused by the short time scales, and that new understanding about the physics of the Earth and the rate of species change physics might vindicate his theory. Writing in his final published statement on the topic he said:

With respect to the lapse of time not having been sufficient since our planet was consolidated for the assumed amount of organic change, and this object, as urged by [Lord Kelvin], is probably one of the gravest as yet advanced, I can only say, firstly that we do not know at what rate species change as measured in years, and secondly that many philosophers are not yet willing to admit that we know enough of the constitution of the universe and of the interior of our globe to speculate with safety on its past duration. (Burchfield, p. 79)

When Darwin died in 1882, he was widely mourned as a great scientist who had convinced the world that the theory of evolution is a fact from which there is no going back. But the vindication of his theory of natural selection had to wait another thirty years.

In the previous post, I said that by the end of the 19th century, geologists had started balking at the ever-reducing ages of the Earth coming out of physicists calculations, most of the latter based on thermal cooling models developed by Kelvin and going back to Buffon. They felt that 100 million years was as far as they were willing to go. Some physicists were also starting to question Kelvin's models and the values of the thermodynamic parameters on which his calculations depended.

Biologists were also getting tired of being pushed around by the physicists. Perhaps emboldened by the resistance from geologists and some physicists, they too started arguing that the evidence from paleonotology for an old Earth was too strong to be dismissed, and that the cause of any discrepancy with the results from physics lay with physics and not with biology.

The professor of zoology at Oxford Edward Poulton (1856-1963), in a talk to the British Association in 1896, picked up on some recent critiques of Kelvin's work by other physicists that had pointed out that if one changed Kelvin's assumptions of the thermal properties of the Earth by relatively small amounts, the age of the Earth could be made to increase by a factor of over fifty. Poulton then made the case as to why the case for an older Earth based on biological and paleontological evidence should not be dismissed. He pointed out that:

[E]volution results first in the divergence of general characteristics and then of specific characteristics, that natural selection requires much longer to alter simple organisms than more complex ones, and that the origin of no phylum can be found anywhere in the stratified record – he proceeded to argue that the degree of specialization found in the lower fossils can only be accounted for by a very long period of evolution prior to the beginning of geological record. (Burchfield, p. 139)

He concluded that the physicists must be wrong about their young Earth.

This was the state of affairs near the dawn of the twentieth century. It was an impasse, with geology and physics at loggerheads, and the theory of evolution by natural selection hanging in the balance, whose fate would be decided by which side would emerge the ultimate winner.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: Andrew Schlafly on The Colbert Report

I have written about Andrew Schlafly and his wacky Conservapedia project before (see here and here) but had never seen him before until this interview.

He seems a little weird and creepy to me.

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December 14, 2009

The age of the Earth-8: Geologists at loggerheads with physicists

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

While Kelvin's estimate of the age of the Earth was interesting in its own right and faced its own supporters and detractors, the undeniably important consequence of his work was that for the first time, pinning down an actual age for the Earth became a question that had the potential to be definitively answered, and this spurred the growth of an entire research area. What Kelvin did that was of immense importance were two things: he demolished the uniformitarians' vague notions of an almost limitless time for the age of the Earth and established the importance of doing precise calculations; and he began the process, and highlighted the importance, of unifying scientific theories in formerly divergent fields, by introducing physics principles into geological studies.

Kelvin had arrived at an age for the Earth that made it very difficult for natural selection to succeed as a mechanism. Then, as now, results from physics tend to be regarded as on a sounder footing than those from other disciplines. Hence those other fields such as geology and paleontology and biology tend to try and conform to the constraints provided by physics, not the other way around. Kelvin's estimate of 100 million years as the upper limit for the age of the Earth became part of the scientific lore and geologists and biologists scrambled to accommodate it by trying to find ways to modify their calculations to be consistent with this upper bound. They had some success since each of these calculations depended on many parameters whose values could not be determined precisely, and so there was some room for flexibility.

As for evolution by natural selection, this low upper limit for the age of the Earth caused serious problems. As a result of Kelvin's and other people's strong criticisms of the idea of an Earth that was hundreds of millions of years old, by the third edition of Origins, Darwin had abandoned his breezy calculation of a 300 million year old timescale for the formation of the Weald, done somewhat casually at a time when such an age seemed reasonable. Meanwhile Wallace published another book in 1880 that suggested that 200 million years was sufficient for evolution to have worked (Jackson, p. 193). By squeezing here and pinching there, it seemed possible (though just barely) to accommodate 100 million years as sufficient for natural selection to work, but only with great difficulty and at the risk of sacrificing plausibility.

By around 1880, an uneasy truce seemed to have been drawn among the physics, geology, and biology communities around a 100 million year old Earth. But it did not last long. Others came along who followed up on Kelvin's methods and using more refined calculations and newer estimates for the parameters involved, arrived at even shorter ages of 40 million and then 20 million years for the age of the Earth. Most important among these was an 1893 calculation by Clarence King, the first director of the US Geological Survey who, again basically using Kelvin's thermal methods, arrived at a figure of 24 million years. In a paper in 1897, towards the end of his long and illustrious career, Kelvin stated his conclusion that the Earth was between 20 and 40 million years old, with King's value of 24 million being likely most correct.

This caused immense problems for the other areas of science. If it was true, then almost all of geology would have to be drastically re-conceptualized and the theory of evolution by natural selection would have to be thrown out the window, to be replaced by some teleological model of directed evolution that implied planning or design or some other form of supernatural intervention.

But geologists had had enough of conforming to the ever-increasing restrictive limits of the physicists and modifying their parameters accordingly. Their discipline had now been around for about a hundred years and the newer generation of younger geologists no longer felt like new kids on the block who could be pushed around so easily by the big physics bullies. They felt that 100 million years was as far as it was reasonable for them to go given their own methods of estimating the ages of geological features based on rates of formation and erosion and sedimentation. They dug in their heels and became more assertive, saying that the laws of geology were firmly enough established to rule out such a young Earth and boldly suggested that it was physics that had gone awry somewhere, even if they could not find fault in its calculations or point out where the problematic assumptions were.

Next: What about biology and natural selection?

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: If the shoe were on the other foot…

If there is one thing that The Daily Show is particularly good at it is showing how ridiculous something is by reversing roles.

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December 11, 2009

The age of the Earth-7: The Earth starts getting younger again

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

Darwin and Wallace published their theory of natural selection at a time when it seemed that they had all the time they needed for their theory of natural selection to work. But that window of freedom of long geological times was soon to close and, starting around 1860, newer estimates of the age of the Earth started to shorten it considerably. Part of the reason was undoubtedly a backlash to the success of Darwin's theory of evolution that, within a decade of the publication of Origins in 1859, had persuaded almost the entire scientific community that evolution was a fact and that its basic idea that all organisms arose from descent with modifications from common ancestors was true.

Acceptance of evolution did not mean that people had given up on god altogether. Most people, including many in the scientific community, were still religious and sought to find ways to preserve a role for god. While they accepted evolution as a fact, what these people found difficult to stomach was Darwin and Wallace's mechanism of natural selection as the driving force for the process, because this implied that evolution is directionless. Especially troubling was its implication that humans were an accident, not guaranteed to appear, and thus could not be part of any original design plan that god would have had.

There were competing models that preserved this idea of design and thus had a potential role for god and these were the ones favored by religious scientists. Theistic evolution (in which god guided the process of evolution in unspecified ways), orthogenesis (in which it was postulated that organisms contained within themselves a directional mechanism that resulted in continuous improvement), and Lamarckism (in which the acquired characteristics of an organism were somehow transmitted to its progeny) all had the possibility of a role for god, or at least had some directionality that implied that humans were the inevitable result of a grand plan. Natural selection offered no such consolation.

What religious scientists realized was that the smaller the value arrived at for the age of the Earth, the more unlikely it was that natural selection could be the mechanism for evolution. A younger earth implied the need for some agency to speed up the process of evolution and what could that agency be other than god? (In this respect, they were much like modern day intelligent design creationists.) And so there was a strong motivation to lower the upper limits on the age of the Earth and thus strengthen the case for the alternatives to natural selection.

But it must be emphasized that even this was a far cry from the efforts of present day creationists to resurrect a 6,000 year-old Earth. Even the religious scientists of that earlier time had by then rejected that idea with its supernatural catastrophes as absurd and no serious scientist for the past 200 years has even considered that possibility (Burchfield, p. 37). Anyone who argues for such a young Earth has rejected science altogether. These religious scientists accepted evolution as a fact. What they were hoping for is that their methods of estimating the age of the Earth using purely scientific methods would yield results that were of the order of a hundred million years or less, which would be too tight a timescale for natural selection to work.

It was the physicist William Thomson (1824-1907), better known by his later title of Lord Kelvin, who seriously threatened to overthrow the natural selection mechanism for evolution. Kelvin was opposed to evolution by natural selection because it seemed to rule out design in nature and thus left no role for god (Burchfield, p. 33). Kelvin had already established a reputation as one of the foremost physicists of his day, pioneering important work in the study of thermodynamics, especially with the first law (that dealt with the conservation of energy) and the second law (that dealt with the dissipation of heat energy and the consequent directionality of heat flow). So his words were taken seriously, since physics was seen as the most well-established of scientific disciplines.

What Kelvin did was to apply the laws of physics to three different kinds of calculations for the age of the Earth: calculating the age of the Sun to set an upper limit, examining the role that tidal friction played in shaping the Earth, and treating the Earth as a solid cooling body, all of which gave him similar results, persuading him that he was on the right track (Jackson, p. 200).

In the most important of those methods, the cooling method, what Kelvin did was similar to the idea of Buffon in 1778, except that the laws of physics, especially thermal physics, had advanced considerably since Buffon's time, and Kelvin himself had played a major role in that advancement. Kelvin assumed that all the Earth's (and Sun's) energy originated as gravitational and mechanical energy in the particles and possibly meteors that preceded its formation, and that as they coalesced to form the Earth, this gravitational energy was transformed into heat energy that made the Earth into a hot molten ball. The Earth then gradually cooled and solidified as this heat was slowly radiated away into space.

Knowing the mass of the Earth and the Sun and making various assumptions about the initial kinetic energy of the particles, the state of the Earth's core, and the rates of conductivity of heat from that core to the surface and radiation into space, in 1862 Kelvin came up with upper limits for the ages of both, captured in his statement that the Sun "has not illuminated the earth for 100,000,000 years, and almost certain that he has not done so for 300,000,000 million years." He also estimated that the Earth was somewhere between 20 million and 400 million years old, with the likely figure being 98 million (Burchfield, p. 36). In 1868, he revised his calculations and made an even stronger statement, that the Earth was no more than 100 million years old (Burchfield, p. 43). He thus flatly contradicted Darwin's calculations of 300 million years for the time taken for the denudation of the Weald.

Kelvin had thrown down the gauntlet to the geologists and biologists and the next fifty years would result in a struggle to see which side would emerge the winner: the young Earthers of that time (which meant ages of less than 100 million years, not the ridiculous 6,000 years of the present-day creationist young Earthers) or the old Earthers.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: Playing dumb

If there is anything more annoying than people who pretend to be smarter and more knowledgeable than they are, it is people who pretend to be stupider than they are.

What is particularly sad is that Fox News must think their viewers don't like people who actually know stuff and would prefer the stereotypical dumb blonde.

The Daily Show With Jon StewartMon - Thurs 11p / 10c
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December 10, 2009

The age of the Earth-6: A time window opens for natural selection

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

In the early 1800s geology became recognized as a formal professional discipline. Societies were formed, university professorships were created, systematic surveys studies began to be done of geological strata, and detailed classifications made. In this period Charles Lyell (1795-1875), with the first volume of his book Principles of Geology (1830), emerged as a leader in the new field. His book was a best seller, selling 15,000 copies in its first edition and going through ten subsequent editions.

He too argued the uniformitarian position that the Earth was extremely old, though not infinite, and that this enormous time was sufficient to produce all geological features through the process of very small but cumulative changes. He argued in favor of the model of actualism, the idea that the present rate of geological change could be assumed to be constant over time and thus could be used to extrapolate backwards to find out when specific geologic features began to be formed. As Lyell put it, "the present is the key to the past" (Jackson, p. 130). Lyell and the other uniformitarians were successful in persuading all but the most religiously hidebound that the Earth was far older than one would calculate using the Bible, and by around 1850 this idea was predominant though, as I discussed in the previous post in this series, not unchallenged.

The importance of this development and its timing cannot be overemphasized. It was during this same period (1830 to 1860) that Charles Darwin and Alfred Russell Wallace were working out their theory of evolution by natural selection. They knew that their proposed mechanism of tiny incremental changes in organisms cumulatively leading to major changes had to be very slow and thus required long times. The rise to dominance of uniformitarian thinking in geology (which argued similarly for tiny changes producing big effects) and the almost unlimited time of existence for the Earth that this model projected would have been enormously liberating for them and allowed them to explore their ideas unfettered by constraints that would have inhibited someone living even just a few decades earlier.

Darwin was given Lyell's book to read on his voyage on the Beagle and it is clear that its ideas deeply influenced him. Lyell became Darwin's good friend and supporter although his religious beliefs prevented him from accepting the godless implications of evolution by natural selection.

Scientific theories are not created in a vacuum. They are strongly influenced by contemporaneous factors. Darwin was fortunate that he was developing his revolutionary theory at a time when the power of religious dogma to limit scientific inquiry was on the wane as science became increasingly decoupled from religion, and the intellectual climate was congenial towards what would in earlier times have been condemned as heresy and perhaps even led to death. He was also fortunate to be the son, grandson, and brother of freethinkers, thus providing him with a personal space of intellectual freedom and support for his heterodox views on the origin of species. The fact that his wife was devoutly religious would have been a hindrance to speaking his mind openly at home but she seems to have confined her concerns to worrying about his physical well-being and immortal soul and not try to influence his scientific work.

Spurred by this openness to the idea of a very old Earth, in the first edition of his Origins (p. 285, 286) Darwin even made a rough estimate of the age of time taken for the 'denudation' (erosion) of a region in Sussex in the south of England known as the Weald, arriving at a figure of 300 million years. This figure must have been reassuring to him, suggesting that he did not have to worry about whether the mechanism of natural selection had sufficient time to work.

(It is not commonly known that Darwin was also an accomplished geologist, developing a keen interest in that subject while still a student and making extensive investigations while undertaking long hikes over the English countryside. Before he published his major work in biology in 1859, he had under his belt a successful theory on the origins of the coral reefs of volcanic islands. He had also published three books on geology: The structure and distribution of coral reefs (1842), Geological observations on the volcanic islands visited during the voyage of H.M.S. Beagle (1844), and Geological observations on South America (1846), all based on his careful observations during his epic voyage.)

The break from biblical chronology triggered by the rise of uniformitarianism also allowed other methods of determining the age of the various geological features to emerge. These involved measuring the rate of sedimentation by which the Earth's crust and river deltas were being formed, the rate of increase of salinity of lakes and oceans, the rate at which the Earth's rotation was slowing due to tidal friction, and the rate at which erosion was creating cliffs, ravines and other steep formations. By calculating the rates at which these phenomena were occurring now and making some assumptions about what their initial states might have been (such as that lakes and oceans may have originally been free of these solutes), people arrived at estimates for the time taken to reach the current state.

All of these methods of calculation gave ages in the ranges of tens of millions and even hundreds of millions of years. Although there was wide disagreement with the ages arrived for each specific feature, people realized that estimating the age of geological features was fraught with imprecision because of the huge uncertainties in making estimates of current rates of erosion and lack of knowledge about the initial conditions and so forth, and so the discrepancies between the various methods, while unsatisfying, did not really constitute a crisis. But what was becoming resoundingly clear was that they were all inconsistent with a 6000 year-old Earth. The Bible had become irrelevant for dealing with this question.

Also, these calculations merely gave the time taken for these features to appear and thus could be considered only as providing lower limits to the age of the Earth, not its actual age, so natural selection still had the freedom to do its slow work in the creation of species, relatively unconcerned by upper limits to the time available.

Next: The Earth starts getting younger again.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: Trailer for The Greatest Action Story Ever Told

Just in time for the holiday season.

December 09, 2009

The age of the Earth-5: Christianity tries to deal with an old Earth

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

By the end of the 18th century, Enlightenment values had taken hold, science and rationality were on the rise, and religion could no longer rely on dogmatic assertions and threats alone to suppress ideas that it found unpalatable. So the strategy shifted to creating alternative narratives that had a scientific veneer that would make their religion-based conclusions more acceptable. That strategy has been the one that religions have followed ever since, right down to the present day, with intelligent design being its latest incarnation.

In reaction to the rise in the mid-19th century of uniformitarianism in geology and its concomitant idea of an old Earth, there was a resurgence of Biblical literalism that manifested itself in an alternative school of thought known as Neptunism, that argued that water was the main cause of changes in the Earth's features. This theory was favored by those of a more religious bent who were seeking ways to reconcile science with the Bible.

Some of the adherents of Neptunism were convinced that the Great Flood of Noah was sufficient to preserve the biblical chronology and this group steadfastly rejected any attempts to make the Earth older than 6,000 years or so. One of the most well known of the proponents of this theory was George McCready Price (1870-1963), who tried to make the case that scientific evidence supported a strictly literal interpretation of the Bible. The numbers of this group remained small until the recent rise of the creationist movement that was facilitated by the publication in 1961 of the book The Genesis Flood by John Whitcomb and Henry M. Morris that built on Price's ideas. While Whitcomb was a theologian, Morris had a doctoral degree in hydraulic engineering with minors in geology and mathematics. He later founded the Institute for Creation Research in 1970 to advance these ideas.

But most religious scientists in the late 18th and early 19th centuries were willing to concede that a strict biblical chronology was too restrictive and required the existence of unrealistically strong forces to create its effects in such a short time. As is the case, when faced with incontrovertible scientific evidence that what they were asserting all along as divinely inspired was simply wrong, sophisticated religious apologists now came up with new interpretations of scriptures that conveniently seemed to conform with an old Earth. They then, as usual, argued that this agreement shows that the Bible is correct because it predicted the scientific discovery of an old Earth!

One version of this new biblical interpretation is what is known as the 'Gap' or 'Ruin-Reconstruction' theory that arose in the early 19th century. This theory conveniently found a 'gap' between Genesis 1:1 ("In the beginning God created the heavens and the earth") and Genesis 1:2 ("Now the earth was [a] formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters") that allowed for an indefinite amount of time and the shoe-horning in of a very old, unspecified age of the universe in which matter was first created, followed by non-human life and the formation of fossils.

This gap allowed for multiple cataclysms and creations and is flexible enough to accommodate most geologic evidence. But when it comes to the first appearance of humans, the model becomes that of standard creationism with a Garden of Eden and the first humans Adam and Eve created in six 24-hour days in 4004 BCE followed in 2348 BCE by Noah's flood, which in this model need not be a global flood but could be a local phenomenon.

A weaker formulation of creationism has an even more flexible structure and is known as the 'Day-Age' model. This allows for a very old, unspecified age of the universe in which matter was first created, followed by life, the formation of fossils, and finally human beings. Noah's flood was a historical event in this model but it could be a local phenomenon. The six 'days' of creation in the Genesis story are interpreted metaphorically as representing long but indeterminate periods of time, whence comes the name of this model, and hence all these events have unspecified dates that can accommodate values obtained using the standard dating techniques of science. Adam and Eve and the Garden of Eden story are also interpreted metaphorically and not as actual historical events. (For a history of evolution of creationist thought, see Ronald Numbers, The Creationists: The Evolution of Scientific Creationism, 1992.)

William Jennings Bryan, a key player in the Scopes trial of 1925, seemed to be a believer in the 'day-age' model but under questioning in the trial, probably for tactical reasons related to the specifics of that case, responded as if he was a believer in the 'gap' model.

Nowadays one rarely finds people who believe in the gap model. Christians seem to be either young-Earth/Flood Geologists or some form of day-agers. Islamic creationists and some sophisticated Christian apologists (such as the intelligent design people) today also seem to adopt the 'Day-Age' model, hoping that it will make the science-religion contradictions less obvious.

But enough of religious apologetics and its sad attempts at rescuing faith using religious and historical revisionism. The next post gets back to the scientific history of calculations of the age of the Earth.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: Jesus Christ – The Musical

December 08, 2009

The new religions, same as the old

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

In recent posts, I have been highlighting the absurdities of religions like Mormonism and Scientology. There is no end to such religious weirdness. There is in India right now a person who calls himself a God-man who has millions of devout and devoted followers, manyy rich and powerful, who visit his ashram and give him money. His name is Sai Baba and he is a household name in the Indian sub-continent. I personally know people who believe his claims that he is an incarnation of god and have tried to persuade me to believe in him too, although there are many serious allegations that he is a pedophile and using magic tricks to create the illusion of having godly powers. See this video of him getting caught using a trick.

People who value rationality and logic and scientific thinking can dismiss all these religions, old and new, as the products of fraud, excessive credulousness, superstition, and wishful thinking, without a shred of credible empirical evidence in support of them. But people who belong to one of these religions have a tougher time explaining why their own religion is more credible than the others. For an example of this, here's what Jacob Weisberg wrote in Slate magazine during the last election when Mitt Romney (a Mormon) was still a candidate, trying to justify why he would not vote for a Mormon or Scientologist for president, while Jews and Christians were just fine with him:

One may object that all religious beliefs are irrational—what's the difference between Smith's "seer stone" and the virgin birth or the parting of the Red Sea? But Mormonism is different because it is based on such a transparent and recent fraud. It's Scientology plus 125 years. Perhaps Christianity and Judaism are merely more venerable and poetic versions of the same. But a few eons makes a big difference. The world's greater religions have had time to splinter, moderate, and turn their myths into metaphor.

In other words, Weisberg says that yes they may all be frauds, but at least the old religions (which conveniently includes his own) have had time to create elaborate justifications for their frauds. Weisberg, though hypocritical and self-serving, is actually right. The only reason that traditional religions are not subject to the same kind of scrutiny that new religions face is because they have long had an army of propagandists (who go by the label of theologians) whose job is to create vague rationalizations that believers can grab onto to convince themselves that what they believe is not utterly absurd. Theology should be defined as the discipline that makes absurd religious beliefs acceptable to people who want or need to believe.

The sophisticated theologians and the average Friday or Saturday or Sunday worshipper have almost nothing in common in terms of beliefs, though they may use a common vocabulary and holy book. Sophisticated theologians think that the beliefs of ordinary people are laughable but they don't say so openly. Their rationalizations are aimed at persuading sophisticated believers. The belief of these people then reassures the 'common' believers that their religion must be believable since all these sophisticated people subscribe to it.

It is quite conceivable that in the future, once they have had sufficient time to get their act together, we will see sophisticated Scientology apologists defend their religion in the high manner of Christian apologists like Karen Armstrong, H. E. Baber, and John Haught (more on him in a future post) arguing that there are 'deep truths' buried in the religion that we silly atheists with our shallow preoccupations with trivial things like evidence and truth, and our childish insistence that things make logical sense, simply cannot appreciate.

Some droll commenters over at Why Evolution is True provide examples of the kinds of verbiage we might see in the future from Scientology apologists, once they get the hang of how theologians in the older religions operate.

The problem is that militant scientology-haters are ignorant of sophisticated sciento-theology. Real scientology is like poetry–it transcends the question of whether Xenu exists. Fundamentalist a-xenuists are just rehashing the long debunked dogma of logical positivism. But if they read some Quine and got more up to speed on their philosophy they’d see the error of their ways. It’s entirely possible for an individual to believe in both Xenu and the science of aerodynamics, so clearly there is no conflict between science and Scientology. (Commenter Wes)

All Scientologists understand that Xenu is in fact a symbolic metaphor for the ground of being in which we all seek meaning. Thetans are sophisticated representations of our own inner journey to understanding, and limn the boundaries of our inner/outer conflict. (Commenter Tulse)

Of course, ordinary believers will find such things preposterous because they want magical thinking. Sophisticated theological language is always aimed at the intelligentsia, to persuade them to stay on board and give the religion credibility in the eyes of the masses. As George Orwell said in his Notes on Nationalism (1945) albeit in a different context: "One has to belong to the intelligentsia to believe things like that: no ordinary man could be such a fool."

POST SCRIPT: Scientology exposed

Scientologists are sensitive to questioning about their beliefs, perhaps because of a realization of how ridiculous it sounds and also because having that knowledge freely available lowers its sale price. Recently the spokesperson for Scientology Tommy Davis walked out of an interview with ABC News's Martin Bashir when he was asked about the Xenu stuff. He later tried (unsuccessfully) to prevent the broadcast of the interview. Watch.

Commenter Eric pointed out an expose of Scientology by the St. Petersburg Times that revealed the take-no-prisoners attitude that the church uses against defectors and those that accuse it of abusive practices.

December 07, 2009

The age of the Earth-4: The strategy of religions in response to scientific advances

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

The history of the science-religion conflict follows a standard pattern. Religions make claims that lie within the framework of science, saying those claims must be true because of their divine origin (because of revelation or religious texts). Then it fights any scientific advances that challenge those claims. Then when the evidence becomes too great and further opposition becomes ludicrous, they concede the point and retreat to a new line of defense. Then after some time has elapsed to allow people to forget its previous objections, religions argue that the very scientific discoveries that they once vigorously opposed now actually support their religious beliefs. They sometimes even go so far as to suggest that their religion actually predicted them. (The comic strip Jesus and Mo has something to say on this here, here, and here.)

A wonderful example of this is the church's persecution of Galileo because of his support for the Copernican heliocentric model of the solar system. The Catholic Church only apologized for this in 1992. But it did not stop there. It went further and suggested that Galileo's research was actually divinely inspired with Pope John Paul II saying, "Galileo sensed in his scientific research the presence of the Creator who, stirring in the depths of his spirit, stimulated him, anticipating and assisting his intuitions (my italics)."

Really? Who knew? Why wasn't the Creator similarly "stirring in the depths" of the spirit of the Pope in Galileo's time to let him know that Galileo was on the church's team and to stop bugging him? And was god so busy with other things that he waited nearly 400 years to correct this misunderstanding that has been one of his church's greatest embarrassments? Ah, the inscrutable ways of god, who works in mysterious ways that we mere mortals cannot comprehend. What we see as incredible stupidity or laziness is actually part of some deep plan that will be revealed to us when we are ready or die.

With regard to evolution, after over a century of opposition, Pope John Paul II in a speech in 1996 to the Pontifical Academy of Sciences made a grudging concession that Charles Darwin may, just may, have been onto something with his crazy ideas:

[N]ew findings lead us toward the recognition of evolution as more than a hypothesis. In fact it is remarkable that this theory has had progressively greater influence on the spirit of researchers, following a series of discoveries in different scholarly disciplines. The convergence in the results of these independent studies—which was neither planned nor sought—constitutes in itself a significant argument in favor of the theory.

(Note how even the Pope recognizes that it is the interconnectedness of modern science, the "convergence in the results of these independent studies", that gives its conclusions such strength.)

It took fourteen years for the other shoe to drop on evolution, with the church now actually claiming credit for the basic idea of evolution. Archbishop Gianfranco Ravasi, head of the Pontifical Council for Culture, said just this year that "while the Church had been hostile to Darwin's theory in the past, the idea of evolution could be traced to St Augustine and St Thomas Aquinas" (my italics).

Isn't that sweet? They knew about evolution all along but decided to keep it secret for 1,500 years until Darwin spilled the beans, and then fought it for another 150 years, before deciding that it was time to whip off the mask and say that they were the original evolutionists, and that they had just been kidding all along about their opposition to the theory.

The age of the Earth provides another humorous example of the church rewriting history in this way. For example, this Catholic website says that "The Church has always agreed with scientists on matters such as the age of the earth and the authenticity of the fossil record" (my italics) while another Catholic website goes into the usual routine of suggesting that god was inspiring these scientific discoveries all along: "The question about the origins of the world and of man has been the object of many scientific studies which have splendidly enriched our knowledge of the age and dimensions of the cosmos, the development of life-forms and the appearance of man. These discoveries invite us to even greater admiration for the greatness of the Creator, prompting us to give him thanks for all his works and for the understanding and wisdom he gives to scholars and researchers" (my italics).

But of course these ingenuous statements that the church "has always agreed with scientists on matters such as the age of the earth" and been thankful for the "understanding and wisdom he gives to scholars and researchers" is flatly contradicted by the historical record. Buffon's 1778 calculation that the Earth was 75,000 years old considerably upset the religious people of his day and the theologians at the powerful Sorbonne created a huge fuss and demanded that he publish an apology for publishing results that contradicted the biblical chronology. Buffon made some apologetic remarks in later editions of his book but did not withdraw the book or repudiate his conclusions (Jackson, p. 111).

Fortunately for Buffon, by his time freethinking was on the rise, people like Baron D'Holbach were publishing atheist treatises blasting the church and religion, and the church had lost the kinds of punitive powers that it had during the periods of the Inquisition so the church could do nothing more to Buffon than castigate him and he was tough enough to withstand their pressure.

As a result of Buffon's work the genie was now out of the bottle and from then on scientists looked elsewhere than the Bible to answer questions about the age of the Earth. The rise of catastrophism and its concomitant idea of a very old, perhaps infinitely old, Earth came to dominate thinking by around 1850.

Once an old Earth became such an established fact that further opposition to the idea became just silly, how did Christianity respond? That will be discussed in the next posting.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: What if life is found on other planets?

Stephen Colbert explores the implications for Christianity.

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December 04, 2009

The age of the Earth-3: The Earth gets old again

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series on the age of the Earth, see here.

The Enlightenment brought with it the separation of scholarly thinking from religious dogma and this enabled scientists to think much more freely and broadly about all matters, including the age of the Earth.

As the desire for conformity with biblical estimates weakened, scientists started devising theories of the formation of the Earth and the universe and doing calculations that were not explicitly linked to Biblical theories. Immanuel Kant (1724-1793) and Pierre Laplace (1749-1847) created a new model of the universe, the nebular hypothesis, that said that stars and planets originated as clouds of gases. They used Newton's laws of mechanics and his theory of gravitational attraction to explain the formation and evolution of the solar system.

Comte de Buffon (1707-1788) was one of the first to try and determine the age of the Earth using only scientific theories and data. He used estimates of the initial internal heat of the Earth and its rate of cooling to arrive at a value of about 75,000 years, a result that he published in 1778 (Jackson, p. 117). Although the number seems laughably low now, we must remember that he was working before the age of modern thermodynamics and at a time when the Fahrenheit temperature scale and thermometers were just coming into being. Buffon had to estimate the parameters involved in cooling by making judgments of when two objects were the same temperature by the crude methods of actually touching them with his hands.

Buffon's result, though wildly off the mark by modern standards, was a significant development in two ways. First because it used purely scientific theories to arrive at an age and second because the age he reported broke with a Bible-based chronology completely, going well over the 6,000 years that people believed the Bible required.

This development stimulated the field of geology and paleontology as scientists interested in those fields now started to investigate the origins of the Earth and its fossils without the artificial constraints of the biblical chronology. People like Nicolaus Steno (1638-1687) and Robert Hooke (1635-1703) had earlier observed the presence of sea-shells and other fossils on mountain tops, and the patterns in the layers of rock strata, and had used that information to create theories of geological formation, in which rock layers were formed slowly by sedimentation and newer layers of rock lay on top of older ones. But they had not used them to actually try and date the Earth, because the biblical ages were the standard beliefs in their time.

But now their early work became the basis of the new geology, by combining the theory of slowly sedimental formation with the ordering of fossils in the layers of rocks in which they were found. The clear pattern of evolution that emerged of the appearance of fossils in the rock strata (with simpler fossils being found in the older layers lower down and more complex ones in younger layers higher up) led to later paleontologists such as Georges Cuvier (1769-1832) and Jean-Baptiste Lamarck (1744-1829) suggesting that the process of geological formation must have been quite slow, and required far more time than the Genesis story allowed. A few paleontologists even went back to the old idea that the Earth had existed forever. Even though these paleontologists were Christians (Steno, for example, was a priest and Cuvier was religiously orthodox), they all felt that the Bible should not be the source of data for investigating the age of the Earth and that only the evidence of the Earth itself could reveal its origins.

A major development occurred when James Hutton (1726-1797) published a paper in 1785 that argued that catastrophes and great floods were not necessary to explain the features of the Earth; that they could have been caused entirely by the slow and steady accumulation of small changes. In 1788 he argued in a paper that not only was the Earth infinitely old, it would also last forever saying, "The result, therefore, of our present enquiry is that we find no vestige of a beginning – no prospect of an end." (Jackson, p. 92).

This marked the birth of the idea of uniformitarianism and it was clear to this school of thinkers that adopting this meant that the Earth had existed for a vast amount of time. Some thought it extended back infinitely far while others thought it was extremely old, so old that they were not that interested in pinning down an actual age or thought that it could even be done. They assumed that sufficient time was available as needed for their model of slow rate of changes to produce the desired large effects.

Meanwhile, what was the response of Christians to these grave challenges to their biblical chronology? That will be examined in the next post.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: Mr. Deity gets a tour of hell from Lucifer (Lucy)

The Jesus people should add this to their spiel, since they are obsessed with the idea of other people going to hell.

December 03, 2009

Scientology

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

If the rise of Mormonism in recent times is surprising, Scientology is even more so, since it came into being in just the last fifty years. I must emphasize again that the belief structure of Scientology is no more bizarre than that of Christianity or Islam or Mormonism or any other religion. What is surprising that it, like Mormonism, came into being at a time when people had easy access to the story of its founder, stories that had enough suspicious elements that should have made any reasonable person wary as to his bona fides.

To get a lot of information on this strange organization and its beliefs you can see this website which contains a wealth of categorized information and is run by someone who makes no bones about the fact that he is not sympathetic to the organization.

Here is an illustrated history of Scientology.

Basically Scientology started around 1950 and has as it central myth a story involving a malevolent extra-galactic despot named Xenu who, with the help of psychiatrists, brought a large number of the aliens from the planets in the galaxy he lived in to Earth seventy-five million years ago.

We are told that these people were brought in galactic rockets that looked like DC-8 airplanes, an odd coincidence when you think about it, since that was the shape of commercial airliners that were becoming popular on Earth at that time. Once they reached Earth, Xenu destroyed these aliens and their spirits were captured, given false memories, and stored until humans appeared on Earth at which point those spirits were inserted into them. As a result, they now infect every human being on Earth, causing them misery and suffering, and the implanted false memories are the sources of the other religions.

The basic ideology of Scientology is a confused mess and frankly, I did not think it worth devoting too much time to making sense of it. Apparently, to detect and get rid of the evil influences and memories and thoughts implanted in you by these spirits so that you can reach your full potential, you need to get yourself 'audited'. If you pay the Church of Scientology lots of money, they will 'audit' you using something called an E-meter (which looks like a lie detector but may be just a simple galvanometer that detects electric currents) to determine how much the bad influences have you in its grip and prescribe remedies to get rid of them, in addition to revealing to you the details of your past lives.

Scientologists also say that each of us is possessed of an immortal soul that is trapped in our bodies that is released and becomes re-incarnated upon our death, a model that is similar to that of Buddhism. While Hinduism also believes in reincarnation, Scientology, unlike that religion, does not seem to believe in god.

Who created this religion that sounds like something out of a science fiction novel? None other than a science fiction writer named L. Ron Hubbard. Yes, that makes it really credible, doesn't it? Scientology grew out of Hubbard's earlier promotion of a mental health treatment called 'dianetics' that had many of these features already. Once the soul, as a result of all this auditing, is freed from all the restrictions caused by these evil spirits created by Xenu, it can achieve great things.

Many people have joined this religion, including celebrities such as Tom Cruise and John Travolta and Kirstie Alley. They will tell you that the reason for their career success is that they have got rid of the evil spirit influences that were holding them back. What more convincing testimony do you need that Scientology is the right religion than their great acting performances? Who can forget that classic of film Look Who's Talking starring Travolta and Alley? Okay, so that was not a good example, but you get the idea.

The Scientology organization is both secretive and aggressive, quick to ostracize those who leave the religion and take legal action against anyone who criticizes it. It has recently been suffering some setbacks, though. The government in Australia is threatening to launch a parliamentary inquiry into the church after a senator made a scathing attack on it, based on allegations that he had received from former members that "implicated the organisation in a range of crimes, including forced imprisonment, coerced abortions, physical violence and blackmail."

In France, the organization was convicted of fraud and hefty fines were levied on it. Unlike in the US, France does not recognize Scientology as a religion, "arguing that it is a purely commercial operation designed to make as much money as it can at the expense of often vulnerable victims." The US with its tax-exemption loophole for religions is a magnet for people who are willing to prey on the gullible and separate them from their money.

Scientologists have tried to keep their origins story and practices a closely guarded secret to be revealed only to those who reach exalted levels within the organization (which does not come cheap) but the internet has blown that wide open and the stories are now all over the place. Now with the click of a mouse you can learn all about Xenu and volcano myths and thetans that formerly you had to shell out a lot of money for.

A Cleveland reporter describes his experience with auditing when a Scientology branch office opened here in 2007, along with the mind-boggling prices they charge, such as $50,000-$60,000 (!) for the full auditing program. Maybe this is why they target Hollywood celebrities so much, people who often have more money than sense. Scientology does not seem to have caught on much in the Cleveland area. I was on a panel once with a Scientologist last year at our university but at that time, I had no idea about Xenu and the gang or I would have asked him about it.

I am unsure of the ultimate origins myths of Scientology. It seems obscure. Everything I read starts with the extra-galactic machinations of Xenu and the shenanigans of the spirits that sort of play the role of source of evil. But where did Xenu and the inhabitants of the galaxy they came from originate? Do people still exist in those galaxies? Maybe science fiction writer and Scientology originator Hubbard died before he could invent a back story for them. Or perhaps, given their strong commercial business model, they only reveal this precious secret to people who can afford to shell out money at the highest levels, such as Tom Cruise. So tell us, Tom. Inquiring minds want to know.

But the internet is a wonderful thing with its free flow of knowledge. So I am sure that the knowledge is out there if one is willing to dig deep enough.

POST SCRIPT: South Park on Scientology

For a quickie introduction about the basic origins story of Scientology, watch this clip from a 2005 episode of South Park in which the secrets of Scientology are revealed to Stan because church members believe him to be the reincarnation of their founder L. Ron Hubbard.

The absolutely hilarious full South Park Scientology episode titled Trapped in the Closet (featuring Tom Cruise) is well worth watching.

December 02, 2009

The age of the Earth-2: The Earth gets its first birth day

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

For previous posts in this series, see here.

For a long time, people were comfortable with the idea that the Earth and the universe might have been in existence for an infinite time and is undergoing repeated cycles of creation and destruction.

Things changed with the arrival of Christianity. That particular religion could not tolerate the idea of the universe occurring in cycles because that would mean that Jesus was dying over and over again for our sins, which seemed preposterous. (The discovery of sentient life on other planets is going to create problems for fundamentalist Christians as it is not clear how they would fit into the whole 'original sin and Jesus sacrifice' model.) So there had to be a chronology with a definite beginning and this acted as a spur to make calculations to fix the date of creation. Theophilus of Antioch (~115-183 CE), a convert to Christianity, provided an early estimate that the Earth had existed for 5,698 years until his time (Jackson, p. 13) and Julius Africanus (~200 CE) gave the creation date as 5500 BCE (Burchfield, p. 4).

These Christians based their calculations using an interpretation of the Bible (found in Psalms 90:4 and 2 Peter 3:8) that held that the Genesis story of six 'days' of creation was a metaphor, where each 'day' represented 1,000 years. The total of six days of creation was interpreted as meaning that the universe would last a total of 6,000 years. The appearance of man on the sixth day of the Genesis story represented the arrival of Jesus sometime in the last 1000 years. These calculations, based as they were on metaphorical readings of the text, lacked a certain rigor.

It took until the 1600s for the age of the Earth to become really quantified, with scholars getting down to the nitty-gritty of calculating an actual age, with the Bible again being the main source of data, and the results obtained strongly influenced thinking in the Western world. I have written before of Bishop Ussher's (1580-1656) calculation of October 22, 4004 BCE as the day of creation (see part 1 and part 2 ) but his was just one, and not even the first, of many precise calculations around that time that used various versions of the Bible and thus arrived at slightly different values that rarely differed by more than a thousand years.

Why there was such an explosion of so many calculations done in the early 1600s is a bit of a mystery. One suggestion is that people began to realize that if the Earth was only going to last exactly 6,000 years total, then the end of the world was quite near and hence calculating the exact age of the Earth was of practical importance. After all, if you knew for sure that the world would end in a specified year with the return of Jesus, then you could make appropriate plans, or so at least religious people think though I am at a loss as to what one might do. One finds the same kind of obsession amongst present day Rapturists. They work feverishly to look for signs of the end times because they think it is very near. People seem to be strangely drawn to the idea of an imminent apocalypse, as can be seen in the commercial success of films based on that theme.

The first Bible that had carried a chronological marginal creation date was published in 1679 but it was the insertion of the creation date of 4004 BCE and the dates of other significant biblical events next to the relevant sections of Genesis in the annotated versions of the authoritative King James Bibles in 1701 that cemented that date in the public consciousness. These marginal dates continued to be printed until the late 20th century. Ussher was not cited as the source of the dates and may not even have been the source since there were other chronologies, such as that of William Lloyd (1627-1717) who became the Bishop of Worcester in 1699, that also arrived at the date of creation as 4004 BCE. Since the latter was considered the foremost chronologer of his time, he may well have been the source of the date with which Ussher is now indelibly linked, although it is also possible that his calculations were strongly influenced by Ussher's earlier work (Jackson, p. 30).

Whatever the original source of the date, the blame for leading present day fundamentalist Christians into an anti-science cul-de-sac from which they have never emerged surely must lie at the feet of John Fell (1625-1686), Bishop of Oxford and Dean of Christ Church College and the person who for some time controlled the operations of the Oxford University Press. It was he who in 1672 proposed putting the creation date in the King James Bible. If not for that, it is possible that the idea of a 6,000 year-old Earth may have remained a speculation, one among many, that could be interpreted away as science advanced, as has happened to so many other beliefs. But putting it in the hugely influential King James Bible raised it to the level of an infallible truth for many Christians because of their belief that if something is in the Bible, it must be literally true.

Western scientists at that time (or natural philosophers as they were then known) were mostly Christians and while they may not have been as convinced about the ideas of end of the world and Jesus coming again, they saw no reason to challenge the Bible-based calculations as to the date of creation. They took their cue from these biblical calculations and saw their purpose as trying to explain how life could have appeared and how geological forces could produce the features of the Earth, such as mountains and ravines, within that short time. This naturally led to biological theories of special creation and geological theories of catastrophism, a model in which sudden and violent upheavals produced major geological changes.

While some Christians then (and young Earth creationists now) may have seen Noah's flood as the single major catastrophe that produced all the main features, other less Biblically-literal minded scientists such as Rene Descartes (1596-1650) and Gottfried Wilhelm Leibniz (1646-1716) were willing to consider multiple catastrophes, with fire and water as the agents of these major changes, while still sticking with the biblical chronology (Burchfield, p. 5).

But with the Enlightenment, the desire for conformity with biblical estimates weakened, and people started devising theories of the formation of the Earth and the universe and doing calculations that were not explicitly linked to Biblical stories. These developments will be examined in the next post in the series.

(Main sources for this series of posts are The Chronologers' Quest: The Search for the Age of the Earth (2006) by Patrick Wyse Jackson and Lord Kelvin and the age of the Earth by Joe D. Burchfield (1975).)

POST SCRIPT: Book signing and reception

Tomorrow (Thursday, December 3, 2009) there will be a short talk by me on my latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom, followed by a book signing and reception. All are welcome.

Where: Flora Stone Mather room at the Kelvin Smith Library, Case Western Reserve University
Time: 3:00-4:00 pm

December 01, 2009

Origins of religion

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

I sometimes hear the argument that Judaism must be true since so many people would not have been fooled by a scam such as a priest, on instructions from his king, creating their texts and claiming that they were of divine origin. I hear that kind of argument from Christians too who say that Jesus's disciples would not have believed and propagated the claim that Jesus rose from the dead, an incredible story, unless it had really happened and they had seen it for themselves.

Those who think that their own religion must be true because it is highly unlikely that so many people could be gullible enough to be fooled by a false prophet's claims should bear in mind how other religions began because each one has a similar incredible origin and they can't all be true. So we have direct evidence that large numbers of people can be fooled in precisely this way.

rightreligion.gif

For example, Islam originated around 600 CE and has a prophet claiming to be god's messenger and receiving god's sacred words. Recall that Arab culture was very advanced with highly sophisticated mathematics and science. And yet enough people believed his story about riding to heaven on a winged white horse to chat with Adam and Noah and the rest of the gang, and that an angel spoke to him (when no one else was around, of course) and revealed god's words and intentions, which often coincided conveniently with what served his own needs.

The story screams out that it is a hoax or at best that he was suffering from severe hallucinations. And yet enough people believe it that now one in four people around the globe is a Muslim.

For a more recent example take the Mormon religion that came into being a little more than 150 years ago. Their founder and 'prophet' Joseph Smith claimed to have discovered golden plates that contained god's revelations to him and enough people believed him that he was also able to create a new religion that is growing in numbers even now.

What is amazing about this is how obvious is the hoax that Smith pulled. After all, no one else ever saw the golden plates or the angels that he said appeared to him. The plates were supposedly written in some strange language that only he had the means to translate, and then disappeared after he had done so. He himself had a record of being a conman. And just as in other religions, there is a whole lot of wackiness in its mythology. Every element in this story screams out that it is a fraud. And this happened at a time when there were newspapers and other media that could spread the truth about him. And yet enough people believe this so that now the Mormons are one of the fastest growing religions.

The Mormon creation story is not wilder than any of the other creation stories of other religions but it seems so because it is not as familiar and the novelty of it makes it harder to accept for outsiders. With religious myths, familiarity breeds contentment, which is why children are indoctrinated with their religious myths when they are young.

Or what about Scientology? This religion was created in 1950 by its own 'prophet' L. Ron Hubbard and has an origins story that is as wild as that of the Mormons or other religions. It too now has quite a following. (I'll write more about Scientology in a later post.)

If all this can happen as late as in the nineteenth and twentieth centuries with our advanced science and easy access to knowledge about its founders, it shows how easy it is for charismatic people to create religions using simple tricks to fool people into becoming believers and followers.

I think that if someone was determined enough and had some charisma, he could probably make belief in Santa Claus into a major religion. After all, many of the required elements are already in place. We already have enduring myths and legends about him. He has magical powers with his flying reindeer and sleigh and the ability to travel vast distances in a short time. There are already songs about him. Children already believe in him. What prevents him from being a religious figure is that adults deliberately disabuse their children of belief in Santa Claus as they get older. All it would take is for some adults to perpetuate that belief into adulthood for the religion to take hold.

In the cartoon strip Peanuts, every Halloween season would find Linus speaking about his belief in the existence of the Great Pumpkin, who would reward the child who had the most 'sincere' pumpkin patch. And every year, Linus would sleep in his pumpkin patch on the night before Halloween night hoping to catch a glimpse of the Great Pumpkin. Each year he was disappointed but after some sadness his faith would return. The late cartoonist Charles Schulz, creator of the classic strip, was an atheist and I think that this was his wry take on religion because, after all, what is religion except childish beliefs retained into adulthood, and what is religious faith but 'sincere' belief in the nonexistent?

greatpumpkin.full.gif

POST SCRIPT: History of Mormonism in cartoon form