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July 22, 2008
Scientific consistency and Conservapedia loopiness
One of the drivers of scientific research is the desire to seeking a greater and greater synthesis, to seek to unify the knowledge and theories of many different areas. One of the most severe constraints that scientists face when developing a new theory is the need for consistency with other theories. It is very easy to construct a theory that explains any single phenomenon. It is much, much harder to construct a theory that does not also lead to problems with other well-established results. If a new theory conflicts with existing theories, something has to give in order to eliminate the contradiction.
For example, Darwin's theory of evolution is a slow process, incompatible with the young Earth creationist theory of a 6,000-year old Earth. The acceptance of Darwin's theory was only made possible with the almost concurrent emergence of geological theories that argued that the Earth was far older than that. Creationists, on the other hand, want to go in the opposite direction and seek to discredit evolution so that they can hold on to a young Earth.
But while the scientific search for overall consistency results in more logical and satisfying theories and new breakthroughs, the parallel religious attempt to build consistency around a 6,000 year Earth leads to greater and greater loopiness, to the construction of an alternative reality that one can only marvel at.
Take for example, the fascinating response of some religious people to reports of Richard Lenski's interesting evolution experiment I wrote about yesterday. Andrew Schlafly (son of Phyllis Schlafly, a conservative icon) is the founder of Conservapedia, a religious alternative started to counter what they perceive as the anti-Christian, liberal agenda of Wikipedia. Conservapedia views everything through a Christian, right-wing, America-centered lens. It gives a lot prominence to arguments in favor of a 6,000-year old Earth.
The anti-evolution crowd contains many people who combine ignorance of science with arrogance and Schlafly exemplifies this. Even though he is not a microbiologist, he challenged Lenski's work with extraordinarily rude letters implying that there was shady work afoot and demanding to see the raw data, leading to a back-and-forth correspondence. You can read all the gory details here. Lenski's second reply to Schlafly is a masterpiece, combining a lesson in how to get slapped around politely with a good scientific explanation of his experiment.
One benefit of Schlafly's crusade is that Lenski's experimental results became elevated from something that just his biology subcommunity knew about to an internet phenomenon, widely discussed in the wider science and religion world. I myself heard about Lenski's work only because of the fuss that Andrew Schlafly created, so thanks Andy!
If you have not yet experienced the goofiness of Conservapedia, you are missing a treat. Take this gem from its article on the theory of relativity.
A prevailing theory among creation scientists such as physicist Dr. John Hartnett believe that the Earth was once contained in a time dilation field, which explains why the earth is only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe. It is believed that this field has since been removed by God, which explains why no such time dilation has been experienced in modern times. (my italics)
That is a typical religious explanation for phenomena – god did it and then hid the evidence that he did it. It always amazes me that these people claim to know exactly what god does and what god wants but plead ignorance as to why.
Take, as another example, Conservapedia's article on kangaroos. These marsupials are found only in Australia and the scientific understanding of how this happened involves theories of changes in ocean levels, the splitting apart of continents, and the speciation that results when animal populations get separated geographically and evolve independently from their ancestral forms, and thus diverge from their cousins on other continents.
After devoting just one line to the evolutionary explanation for the origin of kangaroos in Australia, Conservapedia expansively discusses the creationist explanation:
According to the origins theory model used by young earth creation scientists, modern kangaroos are the descendants of the two founding members of the modern kangaroo baramin that were taken aboard Noah's Ark prior to the Great Flood. It has not yet been determined by baraminologists whether kangaroos form a holobaramin with the wallaby, tree-kangaroo, wallaroo, pademelon and quokka, or if all these species are in fact apobaraminic or polybaraminic.
After the Flood, these kangaroos bred from the Ark passengers migrated to Australia. There is debate whether this migration happened over land with lower sea levels during the post-flood ice age, or before the super-continent of Pangea broke apart.
The idea that God simply generated kangaroos into existence there is considered by most creation researchers to be contra-Biblical.
Notice that this article disparages the notion that god created kangaroos out of nothing in Australia, but finds perfectly plausible the idea that god created the kangaroos out of nothing earlier, saved just a pair of them in Noah's Ark, and then after the flood had them hopping over to Australia to raise a family start a new life, like homesteaders in old Western films.
One would think that once one allowed that kangaroos could be created out of nothing, Ockham's razor would prefer the former theory. The only reason not to do so is to conform to Biblical myths. The Noah's Ark bottleneck has to be preserved at all costs.
It is a long journey from Mount Ararat in Turkey (where the Ark supposedly finally ended up) to Australia and this theory requires that the pair of kangaroos from the Ark either live long enough to get to Australia before they started breeding or that all their offspring produced along the way stuck with the family for the entire journey (can you imagine how maddening their cries of "Are we there yet?" would become) or that the successor lines of all the ones that were left behind along the way became extinct, leaving no fossil record anywhere else in the world. Or maybe they were raptured early.
Another possibility (which I just thought up or maybe it was god revealing the truth to me, undeserving heathen though I am) is that Noah's Ark was less like an emergency lifeboat and more like a round-the-world cruise ship, and that different animals left the liner at different ports of call: kangaroos at Sydney, koalas at Auckland, penguins in the Antarctic etc. This theory actually explains a lot about the geographic diversity of species and I offer it free to the creators of Conservapedia to add to their site.
Since Conservapedia, like Wikipedia, is a fairly open system that allows almost anyone to edit its entries, some suspect that much of the site's content consists of subtle parodies by people pulling the legs of Schlafly and his co-religionists, and that they have not cottoned on to it yet. For example, I found the above passage about relativity just last week but today noticed that the passage has been changed, to be replaced by the briefer "Prevailing theories among creation scientists such as physicists Dr. Russell Humphreys and Dr. John Hartnett are time dilation explains why the earth is only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe." Was the original a parody that the site editors discovered and scrubbed? Is the kangaroo explanation a parody? It is hard to tell.
It is a sad reflection on your credibility when readers cannot tell when the material has been created in good faith and when it is a hoax.
POST SCRIPT: Platypus
Steve Benen points out that new research mapping the genome of the platypus causes yet more headaches for creationists.
July 21, 2008
Seeing evolution in real time
Evolution opponents tend to try and dismiss the evidence in its favor, as a last resort often resorting to the argument that no one has actually seen evolution occurring and a new species emerging, with all the intermediate stages clearly identified. One reason for this is, of course, that evolutionary change occurs very slowly, not visible in the transition from one generation to another. The emergence of a new species is almost always a retrospective judgment, made long after the fact, of a process that often takes thousands, or tens of thousands, of generations. By that time, most of the intermediate forms have become extinct and left no trace, since fossilization is such a rare event.
This is why researchers are finding that bacteria and other microbes, organisms that can go through multiple generations in a single day, to be valuable targets for study, allowing them to see evolutionary change and speciation within the span of a human lifetime.
In a truly remarkable piece of work, Richard Lenski of Michigan State University, starting from a single E. coli bacterium in 1989, kept breeding them in environments with a limited supply of food to see how they would adapt to their situation.
The experiment ran as follows:
He created 12 identical lines of E. coli and then fed them a meager diet of glucose. The bacteria would run out of sugar by the afternoon, and the following morning Dr. Lenski would transfer a few of the survivors to a freshly supplied flask.
From time to time Dr. Lenski also froze some of the bacteria from each of the 12 lines. It became what he likes to call a “frozen fossil record.” By thawing them out later, Dr. Lenski could directly compare them with younger bacteria.
Within a few hundred generations, Dr. Lenski was seeing changes, and the bacteria have been changing ever since. The microbes have adapted to their environment, reproducing faster and faster over the years. One striking lesson of the experiment is that evolution often follows the same path. “We’ve found a lot of parallel changes,” Dr. Lenski said.
The clever part of this experiment was that by freezing samples every 500 generations or so along the way, Lenski could go back in time if necessary and identify when specific changes occurred. He now has over 40,000 generations of bacteria and has thus been able to track closely the way that random mutations and natural selection, the fundamental basis of evolution, works. What these and other similar experiments do is show evolution occurring in real time.
One result of his experiments is that the bacteria are now twice as big as their common ancestor and reproduce 75 percent faster.
But the more dramatic result that Lenski observed was that after 33,127 generations, suddenly one of the colonies of the E. coli bacteria evolved the ability to absorb citrate, a nutrient found in abundance in the broth in which the bacteria are cultured. One of the signature marks of standard or 'wild' E. coli is their inability, unlike many other microbes, to absorb citrate.
Science reporter Carl Zimmer, who has been following these experiments, reports on the analysis they did of what happened.
[Lenski's graduate student Zachary] Blount took on the job of figuring out what happened. He first tried to figure out when it happened. He went back through the ancestral stocks to see if they included any citrate-eaters. For the first 31,000 generations, he could find none. Then, in generation 31,500, they made up 0.5% of the population. Their population rose to 19% in the next 1000 generations, but then they nearly vanished at generation 33,000. But in the next 120 generations or so, the citrate-eaters went berserk, coming to dominate the population.
This rise and fall and rise suggests that the evolution of citrate-eating was not a one-mutation affair. The first mutation (or mutations) allowed the bacteria to eat citrate, but they were outcompeted by some glucose-eating mutants that still had the upper hand. Only after they mutated further did their citrate-eating become a recipe for success.
So we see the clear emergence of a new form of E. coli, able to live on citrate in a way that 'wild' E. coli are not found to be able to do. The fact that these bacteria developed the ability to switch their diet from the meager glucose to the abundantly available citrate is a significant evolutionary step, showing how an organism can adapt to its environment in ways that make it better able to survive.
This really is a beautiful experiment, illustrating once again how much of science depends on painstaking, long-term, careful study.
Next: Religious anti-evolutionists attack Lenski's work.
POST SCRIPT: Comedian Dave Allen on the story of Genesis
June 27, 2008
The difference between human and other animal communication
In his book The Language Instinct (1994) Steven Pinker pointed out two fundamental facts about human language that were used by linguist Noam Chomsky to develop his theory about how we learn language. The first is that each one of us is capable of producing brand new sentences never before uttered in the history of the universe. This means that:
[A] language cannot be a repertoire of responses; the brain must contain a recipe or program that can build an unlimited set of sentences out of a finite list of words. That program may be called a mental grammar (not to be confused with pedagogical or stylistic "grammars," which are just guides to the etiquette of written prose.)
The second fundamental fact is that children develop these complex grammars rapidly and without formal instruction and grow up to give consistent interpretations to novel sentence constructions that they have never before encountered. Therefore, [Chomsky] argued, children must be innately equipped with a plan common to the grammars of all languages, a Universal Grammar, that tells them how to distill the syntactic patters out of speech of their parents. (Pinker, p. 9)
Children have the ability to produce much greater language output than they receive as input but it is not done idiosyncratically. The language they produce follows the same generalized grammatical rules as others. This leads Chomsky to conclude that (quoted in Pinker, p. 10):
The language each person acquires is a rich and complex construction hopelessly underdetermined by the fragmentary evidence available [to the child]. Nevertheless individuals in a speech community have developed essentially the same language. This fact can be explained only on the assumption that these individuals employ highly restrictive principles that guide the construction of grammar.
The more we understand how human language works, the more we begin to realize how different human speech is from the communication systems of other animals.
Language is obviously as different from other animals' communication systems as the elephant's truck is different from other animals' nostrils. Nonhuman communication systems are based on one of three designs: a finite repertory of calls (one for warnings of predators, one for claims of territory, and so on), a continuous analog signal that registers the magnitude of some state (the livelier the dance of the bee, the richer the food source that it is telling its hivemates about), or a series of random variations on a theme (a birdsong repeated with a new twist each time: Charlie Parker with feathers). As we have seen, human language has a very different design. The discrete combinatorial system called "grammar" makes human language infinite (there is no limit to the number of complex words or sentence in a language), digital (this infinity is achieved by rearranging discrete elements in particular orders and combinations, not by varying some signal along a continuum like the mercury in a thermometer), and compositional (each of the finite combinations has a different meaning predictable from the meanings of its parts and the rules and principles arranging them). (Pinker, p. 342)
This difference between human and nonhuman communication is also reflected in the role that different parts of the brain plays in language as opposed to other forms of vocalization.
Even the seat of human language in the brain is special. The vocal calls of primates are controlled not by their cerebral cortex but by phylogenetically older neural structures in the brain stem and limbic systems, structures that are heavily involved in emotion. Human vocalizations other than language, like sobbing, laughing, moaning, and shouting in pain, are also controlled subcortically. Subcortical structures even control the swearing that follows the arrival of a hammer on a thumb, that emerges as an involuntary tic in Tourette's syndrome, and that can survive as Broca's aphasic's only speech. Genuine language . . . is seated in the cerebral cortex, primarily in the left perisylvian region. (Pinker, p. 342)
Rather than view the different forms of communication found in animals as a hierarchy, it is better to view them as adaptations that arose from the necessity to occupy certain evolutionary niches. Chimpanzees did not develop the language ability because they did not need to. Their lifestyles did not require the ability. Humans, on the other hand, even in the hunter-gatherer stage, would have benefited enormously from being able to share kind of detailed information about plants and animals and the like, and thus there could have been an evolutionary pressure that drove the development of language.
Human language was related to the evolution of the physical apparatus that enabled complex sound production along with the associated brain adaptations, though the causal links between them is not fully understood. Did the brain increase in size to cope with rising language ability or did the increasing use of language drive brain development? We really don't know yet.
The argument against a linguistic hierarchy in animals can be seen in the fact that different aspects of language can be found to be best developed in different animals.
The most receptive trainee for an artificial language with a syntax and semantics has been a parrot; the species with the best claim to recursive structure in its signaling has been the starling; the best vocal imitators are birds and dolphins; and when it comes to reading human intentions, chimps are bested by man's best friend, Canis familiaris. (Pinker, PS20)
It seems clear that we are unlikely to ever fully communicate with other species the way we do with each other. But the inability of other animals to speak the way we do is no more a sign of their evolutionary backwardness than our nose's lack of versatility compared to the elephant's trunk, or our inability to use our hands to fly the way bats can, are signs that we are evolutionarily inferior compared to them
We just occupy different end points on the evolutionary bush.
POST SCRIPT: But isn't everyone deeply interested in golf?
If you want yet more reasons why TV news is not worth watching . . .
June 26, 2008
Can animals talk?
One of the most interesting questions in language is whether animals can talk or at least be taught to talk. Clearly animals can communicate in some rudimentary ways, some more so than others. Some researchers are convinced that animals can talk and have spent considerable efforts to try and do so but with very limited results. In the comments to an earlier post, Greg referred to the efforts by Sue Savage-Rumbaugh (and Duane Rumbaugh) to train the bonobo chimpanzee Kanzi to speak, and Lenen referred to the development of spontaneous language in children who had been kept in a dungeon. There have been other attempts with chimps and gorillas named Washoe, Koko, Lana, and Sarah.
One thing that is clear is that humans seem to have an instinctive ability to create and use language. By instinctive, I mean that evolution has produced in us the kinds of bodies and brains that make learning language easy, especially at a young age. It is argued that all humans are born possessing the neural wiring that contains the rules for a universal grammar. The five thousand different languages that exist today, although seeming to differ widely, all have an underlying grammatical similarity that is suggestive of this fact. For example, this grammar affects things like the subject-verb-object ordering in sentences. In English, we would say "I went home" (subject-verb-object) while in Tamil it would be "I home went" (subject-object-verb).
What is interesting is that of all the grammars that are theoretically possible, only a very limited set is actually found in existence. We do not find, for example, languages where people say "Home went I" (object-verb-subject). What early exposure to language does is turn certain switches on and off in the universal grammar wiring in our brains, so that we end up using the particular form of grammar of the community we grow up in. This suggests that language structures are restricted and not infinitely flexible, indicating a biological limitation.
The instinctive nature of language can be seen in a natural experiment that occurred in Nicaragua. There used to be no sign language at all in that country because the children were isolated from one another. When the Sandinistas took over in 1979, they created schools for the deaf. Their efforts to formally teach the children lip reading and speech failed dismally. But because the deaf children were now thrown together in the school buses and playgrounds, the children spontaneously developed their own sign language that developed and grew more sophisticated and is now officially a language that follows the same underlying grammatical rules as other spoken and sign languages. (Steven Pinker, The Language Instinct, 1994, p. 24)
What about animals? Many of us, especially those of us who have pets, would love to think that animals can communicate. As a result, we are far more credulous than we should be of claims (reported in the media) by researchers that they have taught animals to speak. But others, like linguist Steven Pinker, are highly skeptical. When looked at closely, the more spectacular elements of the claims disappear, leaving just rudimentary communication using symbols. The idea that some chimps can be taught to identify and use some symbols or follow some simple spoken commands does not imply that they possess underlying language abilities comparable to humans. The suggestion that animals use sign 'language' mistakenly conflates the sophisticated and complex grammatical structures of American Sign Language and other sign languages with that of a few suggestive gestures.
The belief that animals can, or should be able to, communicate using language seems to stem from two sources. One lies in a mistaken image of evolution as a linear process in which existing life forms can be arranged from lower to higher and more evolved forms. One sees this in posters in which evolution is shown as a sequence: amoebas→ sponges→ jellyfish→ flatworms→ trout→ frogs→ lizards→ dinosaurs→ anteaters→ monkeys→ chimpanzees→ Homo sapiens. (Pinker, p. 352) In this model, humans are the most evolved and it makes sense to think that perhaps chimpanzees have a slightly less evolved linguistic ability than we do but that it can be nudged along with some human help. Some people are also convinced that to think that animals cannot speak is a sign of a deplorable species superiority on our part.
But that linear model of evolution is wrong. Evolution is a branching theory, more like a spreading bush. Starting from some primitive form, it branched out into other forms, and these in turn branched out into yet more forms and so on, until we had a vast number of branches at the periphery. All the species I listed in the previous paragraph are like the tips of the twigs on the canopy of the bush, except that some (like the dinosaurs) are now extinct. Although all existing species have evolved from some earlier and more primitive forms, none of the existing species is more evolved than any other. All existing species have the same evolutionary status. They are merely different.
In the bush image, it is perfectly reasonable to suppose that one branch (species) may possess a unique feature (speech) that is not possessed by the others, just like the elephant possesses a highly useful organ (the trunk) possessed by no other species. All that this signifies is that that feature evolved after that branch separated from the rest of the bush and hence is not shared by others. The fact that nonhuman animals cannot speak despite extensive efforts at tutoring them is not a sign that they are somehow inferior or less evolved than us.
Some efforts to teach animals language skills seem to stem from a sense of misguided solidarity. It is as if the more features we share with animals, the closer we feel we are to them and the better we are likely to treat them. It is undoubtedly true that the closer we identify with some other living thing, the more empathy we have for it. But the solution to that is to have empathy for all living creatures, and not try to convince ourselves that we are alike in some specific ways.
As Pinker says:
What an irony it is that the supposed attempt to bring Homo sapiens down a few notches in the natural order has taken the form of us humans hectoring another species into emulating our instinctive form of communication, or some artificial form we have invented, as if that were a measure of biological worth. The chimpanzees' resistance is no shame to them; a human would surely do no better if trained to hoot and shriek like a chimp, a symmetrical project that makes about as much scientific sense. In fact, the idea that some species needs our intervention before its members can display a useful skill, like some bird that could not fly until given a human education, is far from humble! (p. 351)
While any animal lover would dearly love to think that they can talk with animals, we may have to reconcile ourselves to the fact that it just cannot happen, because they lack the physical and perhaps cognitive apparatus to do so.
Next: The differences between animal and human communication.
POST SCRIPT: Superstitions
One of the negative consequences of religious beliefs is that it leads to more general magical thinking, one form of which is superstitions. Steve Benen lists all the superstitions that John McCain believes in.
It bothers me when political leaders are superstitious. Decision-makers should not be influenced by factors that have no bearing whatsoever on events.
June 25, 2008
When did language originate?
Trying to discover the origins of language is a fascinating scientific problem but the evidence is necessarily indirect. Clearly our bodies' physical capacity to articulate sounds is a biological development. Language had to be preceded by the evolution of the physical organs responsible for vocalization. Those organs must have co-evolved with those parts of the brain that can process language. But this evolutionary history is hard to reconstruct since the voice organs and brains are made of soft tissue and are thus unlikely to fossilize. Even if we could get an accurate fix on when the actual physical ability to speak came into being, this the could only be used to set a limit on the earliest time at which language could have occurred, but tells us nothing of when it actually did.
Since humans have these language organs and our closest existing cousins the chimpanzees do not, and since our branch of mammals split off from chimpanzees about 5-7 million years (or about 350,000 generations) ago, it is theoretically possible for language to be that old and still be consistent with only humans being able to speak.
At the other end, the discovery of cave art in Europe consisting of depictions of animals and humans in carved and painted and sculpted forms by Cro-Magnon humans in the Upper Paleolithic era about 35,000 years ago indicate complex social thinking indicative of the presence of language, suggesting that this sets a limit on the latest time for the origin of language.
But 35,000 to 5-7 million years is a huge time interval and attempts have been made to get a more precise fix on the origin of language. Various approaches have been attempted. One avenue of exploration comes from linguistics: the study of languages themselves and how they evolved. Another is to look at the physiological development of the human body. A third method is to look at the development of lifestyles to discern levels of complexity that suggest the kinds of social organization that would require language. A fourth is to look at the use of tools, to see if there is sophistication and uniformity over a wide area suggesting that knowledge was being shared and transmitted to distant locales.
While these are all promising avenues of research, unfortunately the lines of evidence from these different approaches currently do not converge on a single time, suggesting that we still have a long way to go in determining when language might have arisen.
Starting with linguistics, it is known that the structure of languages is very analogous to the biological tree of living organisms. Just as the fossil and DNA evidence all point to all living things being descended from a common ancestor, the approximately five thousand languages that currently exist exhibit grammar and vocabulary relationships strongly suggestive of the fact that they are all derived from a single common proto-language that existed long ago that evolved and split into branches the way that living organisms did. By tracing that linguistic tree back in time, we may be able to fix narrower bounds on the date of origin of that proto-language.
Steven Pinker argues that since modern humans Homo sapiens first appeared about 200,000 years ago and spread out of Africa about 100,000 years ago, and since all modern humans have identical language abilities along with a universal grammar, it seems likely that language appeared concurrently with the first appearance of modern humans. (Steven Pinker, The Language Instinct, 1994, p. 363, 364) Furthermore, there was a more than a tripling of brain size (from 400cc to 1350cc) during the period between the first appearance the genus Homo (in the form of Homo habilis) about two million years ago until Homo sapiens appeared, suggesting that the brain developed in that period partly in order to accommodate the new language centers. Pinker suggests that since Homo sapiens are us, it seems reasonable that language came into being as long ago as 200,000 years ago.
As for biological development. Richard Leakey explains what it is about the human body that enables speech. (The Origin of Humankind, 1994)
Humans are able to make a wide range of sounds because the larynx is situated low in the throat, thus creating a large sound-chamber, the pharynx, above the vocal chords . . . the expanded pharynx is the key to producing fully articulate speech . . . In all mammals except humans the larynx is high in the throat, which allows the animal to breathe and drink at the same time. As a corollary, the small pharyngeal cavity limits the range of sounds that can be produced. . . Although the low position of the larynx allows human to produce a greater range of sounds, it also means that we cannot drink and breathe simultaneously. We exhibit the dubious liability for choking.
Human babies are born with the larynx high in the throat, like typical mammals, and can simultaneously breathe and drink, as they must during nursing. After about eighteen month, the larynx begins to migrate down the throat, reaching the adult position when the child is about fourteen months old. (p. 130)
The unique position of the larynx in human speech suggests that if were able to identify when it got lowered to its present position, we might be able to determine when we first had the ability to speak. But the problem is that those parts of the body are made of soft tissues and do not fossilize easily. However, the shape of the bottom of the skull called the basicranium is arched for humans and essentially flat for other mammals and this part of the skull is an indicator of how well it can articulate sounds. "The earliest time in the fossil record that you find a fully flexed basicranium is about 300,000 to 400,000 years ago, in what people call archaic Homo sapiens." (Leakey, p. 132)
But of course that does not mean that language developed simultaneously with the basicranium. Leakey says that it is unlikely that language was fully developed among archaic Homo sapiens.
The brain is another indicator of possible language origins. The part of the brain known as Broca's area is a raised lump near the left temple associated with language and the use of tools. Furthermore, the left hemisphere of the brain (which is associated with language) is larger than the right. So if we can find fossilized skulls that indicate the presence of either of these features, that would also indicate the onset of possible linguistic ability. A fossil found nearly two million years ago seems to have just such features. Combined with the discovery of tool-making around this time Leakey thinks it is possible that it was with the advent of Homo habilis (the handyman) about two million years ago that language first started to appear, at least in a very crude form. (Leakey, p.129)
Another strategy is to look at the various tools and other artifacts that humans created and see if there is an increase in sophistication and increased spread of similar designs, which would suggest the sharing of knowledge and ideas and thus speech. The more complex the social structures in which people lived, the greater the need for language. As for tools, although they started being made about two million years ago, the earliest kinds were opportunistic in nature. More conscious tool making began about 250,000 years ago but then stayed static for about 200,000 years. The kinds of ordering of tools that are really suggestive of language does not seem to occur until suddenly about 35,000 years ago, coinciding with the sudden spurt in cave art in the Upper Paleolithic period. (Leakey, p. 134)
So basically the situation is confused. While it is possible that language began to appear in some primitive form as early as two million years ago, it seems more likely that real language skills began about 200,000 years ago. Also it is not clear whether language evolved gradually since that time or whether it remained in a low and more-or-less static state before suddenly exploding about 35,000 years ago into the complex language structures that we now have.
Next: Can animals talk?
POST SCRIPT: Fred and Wilma? Who knew?
The most unforgettable act of the 1969 Woodstock festival was Joe Cocker's rendering of the Beatles' A little help from my friends, a gentle song sung by Ringo Starr, which Cocker turned into an over-the top, weird, air-guitar-playing, frenzied, incoherent performance that looked like he was having some kind of seizure. Throughout it, you kept wondering what the hell he was singing since the lyrics seemed to have only a passing resemblance to the original.
Some helpful soul has now provided captions for Cocker's words. It all makes sense now. Or maybe not.
(Thanks to Jesus's General.)
June 24, 2008
The power of language
One of the things that makes some people uneasy about the theory of evolution is its implication that humans are just one branch in the tree of life, connected to every other living thing through common ancestors, and thus not special in any mysterious way. It is surely tempting to think that we must be somehow unique. Look at the art and culture and science and technology we have produced and for which nothing comparable exists by any other species. How can we explain that if we are not possessed of some quality not present in other species?
One doesn't have to look far to find one feature that distinguishes the human species from all its cousins in the evolutionary tree of life. It is language. Somehow, at some point, we developed the capacity to speak and communicate with each other through well-articulated sounds and that has had a profound impact on our subsequent development. Although the number of phonemes (units of sound) that humans can make (about fifty) is not vastly greater than the number available to apes (about a dozen), we can use them to generate an average vocabulary of about 100,000 words. "As a consequence, the capacity of Homo sapiens for rapid, detailed communication and richness of thought is unmatched in the world of nature." (Richard Leakey, The Origin of Humankind, 1994, p. 122)
Without language, the knowledge of animals is restricted to what they are born with as a result of their evolutionary development (i.e., their instincts) and what they acquire during their own lifetimes. That is necessarily restricted and each generation essentially starts life at the same point in knowledge space as the previous one.
But with language, all that changes. Now knowledge can be passed on from generation to generation and we can learn from our ancestors. Knowledge becomes cumulative and the process accelerated with the discovery of writing about 6,000 years ago, resulting in the ability to store and retrieve knowledge over long times and long distances.
I have sometimes wondered why religious people, always on the lookout for a sign that humans are special in god's eyes and possessed of some quality that could not be accounted for evolutionarily, have not seized on language as that which makes us uniquely human. Why don't intelligent design advocates suggest that it was god's intervention that enabled us to develop the ability to speak?
One advantage to religious people of using the introduction of language as a mysterious sign of god's actions is that it is hard to pin down exactly when and how language started, and thus might make it hard to explain scientifically, making it an even better choice for a religious explanation than the bacterial flagellum or even the origin of life. Language was a significant development in our evolutionary history but how it came about is murky because spoken language leaves no trace.
Of course, the fact that we humans possess a unique feature does not necessarily imply that we are special. After all, elephants can also boast of a uniquely useful organ, the trunk, that can do truly amazing things. It is strong enough to uproot trees and stack them carefully in place. It is delicate enough that it can pick a thorn, draw characters on paper with a pencil, or pick up a pin. It is dexterous enough that it can uncork a bottle and unbolt a latch. It is sensitive enough to smell a python or food up to a mile away. It can be used as a siphon and a snorkel. And it can do many more things, both strong and delicate. (Steven Pinker, The Language Instinct, 1994, p. 340)
Why did only elephants evolve this extremely useful organ compared to which the human nose seems so inadequate? It presumably developed according to the laws of natural selection, just like everything else. But if elephants were religious, they might well be tempted to argue that having a trunk was a sign from god that they were special and made in god's image, and thus that god must have a trunk too.
So uniqueness alone doesn't imply that we are possessed of some spiritual essence. But even if the ability to speak does not confer on us a mystical power, the question of when and how humans developed this profound and incredibly useful ability is well worth studying.
Next: When did language originate?
POST SCRIPT: George Carlin on language
I had written this post on language last week but then learned that comedian George Carlin died yesterday at the age of 71. He pushed the boundaries of comedy and many of his riffs dealt with the hypocritical use of language. His famous routine "Seven words you can't say on TV" ended up in 1973 as a case in the Supreme Court, which ruled that the government did have a right to limit the words used on broadcasts.
That routine is below. As to be expected, there is extensive and repeated use of the seven naughty words so don't watch if such language offends you.
Bonus video: George Carlin was also an atheist who poked fun at the lack of logic underlying religious beliefs.
June 23, 2008
Cloning and stem cell research
In the Appendix of his book The Language of God: A Scientist Presents Evidence for Belief (2006), Francis Collins gives a very clear and brief exposition of the issues involved in stem cell research and cloning, which are not the same thing despite popular impressions.
A human being starts out as a single cell formed by the union of an egg and a sperm. The nucleus of this cell contains the contributions of DNA from each of the two parents and thus all the genetic instructions, while the region outside the nucleus, called the cytoplasm, contains the nutrients and signaling mechanisms that enable the cell to do whatever it is meant to do.
The single cell starts multiplying by copying itself, a process known as mitosis. In the very early stages, all the cells are identical and capable of eventually becoming any specialized cell like a liver cell, blood cell, etc. Such cells are called 'pluripotent' because of their ability to become any of the tissues that make up the body and it is these cells that are called embryonic stem cells and the center of the ethical debate.
Soon these embryonic cells begin to specialize and differentiate into cells that begin to form different organ tissues. They do this by having the DNA start turning switches on and off in its genes. Some of these specialized cells, such as those found in limited amounts in bone marrow, become what are known as adult stem cells in that while they still have the ability to differentiate further, they can do so only into a much more limited variety of adult tissues. Such stem cells are called 'multipotent'.
The promise of stem cell research is that one can use a person's own stem cells to regenerate tissues lost or damaged by all kinds of diseases. Since these cells are not perceived as foreign matter, this would not trigger the body's immune mechanism that rejects foreign tissues, as occurs currently with transplants. At present, this immune response has to be suppressed with powerful drugs, leaving the patient vulnerable to other infections.
The ethical problem is that although adult stem cells can be obtained and used from an adult without harming that person, they have only a very limited flexibility. Pluripotent cells are preferred but at present using such cells results in the loss of the embryos from which they are taken, and this immediately raises the ethical issue of whether by destroying an embryo, we are destroying life.
Currently pluripotent stem cell lines are created during the process of in-vitro fertilization, by taking an egg from a woman, fertilizing it in a petri dish with sperm from a man, and growing the resulting cell in solution containing the necessary nutrients for its growth. After about five days, what is called a 'blastocyst' is formed which consists of about 70-100 cells. This consists of an outer wall of cells encompassing a hollow cavity, and an inner clump of about 30 cells (called the inner cell mass) at one end of the cavity. It is the inner cell mass that eventually turns into the tissues that make up the growing fetus, while the outer wall becomes the placenta.
In-vitro fertilization is done to assist childless couples. The selected blastocyst is implanted in the uterus of either the person who donated the egg (the biological mother) or a surrogate, and once it adheres to the wall of the uterus, it receives oxygen and other nutrients from the mother and develops as any other fetus.
The ethical dilemma arises because the process is not 100% certain, and thus many more fertilized eggs and blastocysts are created this way than are currently used to generate actual pregnancies, and this has resulted in hundreds of thousands of unused fertilized eggs. They are currently kept frozen.
Researchers suggest that these fertilized eggs be used (with the donors' permission) to generate embryonic stem cell lines that can be used for research purposes. To do this, the inner cell mass is extracted from the blastocyst and transferred into a dish containing a culture that enables it to grow. When this is done, the blastocyst is effectively destroyed and cannot be used to create a human.
Opponents of embryonic stem cell research say that even a single fertilized egg cell is a human life and thus the blastocyst created this way should never be destroyed. Others argue that a blastocyst has none of the qualities that we associate with being human and thus destroying it not taking a life.
This dilemma created by scientific advances may be resolved by further scientific advances.
One possible compromise arises from the discovery of the process by which animals have been cloned, starting with the famous cloned sheep Dolly. This process is known as somatic cell nuclear transfer (SCNT). What happened with Dolly is that a single cell was taken from the udder of an adult sheep and its nucleus (containing all the genetic information) was extracted. Then an egg cell was taken and its nucleus removed and replaced with the nucleus that had been extracted from the udder cell.
What one might have expected to have created was a cell that was specialized for udders since one had taken a cell from the udder of an adult and by that time the cell should have become specialized for just that purpose. It was once thought that this process of specilization was irreversible. i.e., once a pluripotent embryonic stem cell becomes an adult stem cell or an adult specialized cell, there was no going back to its unspecialized state.
What researchers found to their amazement was that when the udder cell nucleus was inserted into the egg cell that had had its nucleus removed, the nucleus seemed to effectively go back in time and become like the original embryonic cell that had eventually resulted in the sheep from which the udder cell was obtained. When this was then implanted in a sheep, it grew as if from a single fertilized egg and gave rise to a new sheep (Dolly) that had genes identical to those of the sheep from which the original udder cell was taken.
This process has now been repeated with other mammals like horses, cows, dogs, and cats. Although the Raelians made the spectacular claim that they had used this technique to clone a human being, that seems like a hoax.
As a result of this research, it looks like it should be possible to take a nucleus from (say) the skin cell of an adult human and insert it into an egg cell that has had its nucleus removed and thus create cells that have all the properties of embryonic stem cells. Thus it should be possible to create blastocysts in the laboratory without having them originate in the fusion of sperm and egg, the traditional way in which children are conceived. These stem cells would have DNA identical to those of the adult whose skin cell the nucleus was taken from, and not a fusion of mother and father DNA information, the way an embryo is normally formed.
Of course, if this cell is implanted in a uterus, one could potentially create a cloned human being but no one is suggesting that that be done. In fact, there is strong worldwide opposition to such an act. But if the cell is grown in a petri dish, then it could generate the equivalent of embryonic stem cells for both research and therapeutic purposes.
Would the process of SCNT be considered sufficiently different from the usual process of creating a fertilized egg to be considered not a potential human and thus overcome the ethical problems of stem cell research? That remains to be seen.
POST SCRIPT: Tough times
We know that the troubled economy is hurting many people. The Daily Show looks at how it is affecting the people of Beverly Hills.
June 20, 2008
Bioethical dilemmas
In the Appendix of Francis Collins's book The Language of God: A Scientist Presents Evidence for Belief (2006), he tackles the difficult ethical issues raised by advances in science and medicine, especially in the field of molecular biology. His own major contributions to the human genome have undoubtedly made him acutely conscious of these issues. Collins's describes the science and the issues arising from them very clearly and this Appendix is well worth reading.
Having mapped out the entire human genome, scientists are now in the position of being potentially able to identify the presence of genes that may predispose people to certain diseases or behaviors long before those things have manifested themselves in observable ways. This ability has, of course, some obvious advantages in the prevention and treatment of diseases.
For example, breast cancer has a hereditary component that can be identified by the presence of a dangerous mutation in the gene BRCA1 on chromosome 17. This mutation, which also creates a greater risk for ovarian cancer, can be carried by fathers as well, even though they themselves may not have the disease. In those families in which breast cancer is prevalent, knowing who has the mutated gene and who hasn't may influence how closely they are monitored and what treatments they might be given.
As time goes by, our genetic predisposition to more and more hereditary diseases will be revealed. But is this an unqualified good thing?
On the plus side, having this knowledge may enable those people at risk to take steps (diet, exercise, preventative treatment) that can reduce their risk of actually contracting the disease. After all, genes are usually not the only (or even the main) factor in causing disease and we often have some degree of control over the other risk factors for diseases such as diabetes or blood clotting.
We may also be able to treat more genetic diseases by actually changing an individual's genes, although currently the only changes being made are to the genes in the somatic cells (the ones that make up our bodies) and not the ones in the 'germ' line cells (the ones that are passed on to children via the egg and sperm). At present, there is a scientific and medical consensus that influencing the genes of future generations by changing the germ line is not something we should do.
Furthermore, our bodies' reaction to drugs is also often affected by our genes. That knowledge can be used to individualize treatment, to determine which drug should be given to which patient, and even to design drugs that take maximum advantage of an individual's genetic makeup. This kind of personalized medicine lies in our future.
But there are negatives to this brave new world of treatment. Should everyone have their DNA mapped to identify potential risk factors? And who should have access to a person's genetic information?
Some people may prefer not to know the likelihood of what diseases they are predisposed to, especially in those cases where nothing much can be done to avert the disease or what needs to be done would diminish by too much the quality of life of the individual. Furthermore, they may fear that this information could be used against them. If they have a predisposition for a major disease and this knowledge reaches the health insurance companies, the latter may charge them higher premiums or even decline to cover them at all. After all, the profit-making basis on which these companies run makes them want to only insure the pool of healthy people and deny as much coverage as possible to those who actually need it.
It works the other way too. If someone knows they have a potential health problem but the insurance companies don't, they may choose health (and life) insurance policies that work to their advantage.
So genetic information can become a pawn in the chess game played between the individual and the health (and life) insurance agencies.
This is, by the way, another major flaw of the current employer-based private health insurance schemes in the US. If we had a single-payer, universal health care system as is the case in every other developed country, and even in many developing countries, this problem regarding genetic knowledge would not even arise. Everyone would be covered automatically irrespective of their history, the risk would be spread over the entire population, and the only question would be the extent to which the taxpayers wanted to fund the system in order to cover treatment. That would be a matter determined by public policy rather than private profit. There would still be ethical issues to be debated (such as on what basis to prioritize and allocate treatment) but the drive to minimize treatment to maximize private profit would be absent, and that is a huge plus.
There are other issues to consider. What if we find a gene that has a propensity for its bearer to commit crimes or other forms of antisocial behavior? Would it be wrong to use this knowledge to preventively profile and incarcerate people? It has to be emphasized that our genes almost always are not determinants of behavior but at best provide small probabilistic estimates. But as I have written before, probability and statistics is not easy to understand, and the knowledge that someone has a slightly greater chance of committing a crime can, if publicly known, be a stigma that person can never shake, however upstanding and moral a person he or she tries to be.
There is also the question of what to do with people who want to use treatments that have been developed for therapeutic purposes in order to make themselves (or their children) bigger, taller, stronger, faster, better-looking, and even smarter (or so they think) so that they will have an advantage over others. That thought-provoking film Gattaca (1997) envisions a future where parents create many fertilized eggs, examine the DNA of each, and select only those which contain the most advantageous genetic combinations to implant in the uterus. Collins points out that while this is theoretically possible, in practice it cannot be used to select for more than two or three genes. Even then, there are no guarantees that environmental effects as the child is growing up may not swamp the effects of the carefully selected genes. (p. 354)
Collins argues, and I agree with him, that these are important ethical decisions that should not be left only to scientists but should involve the entire spectrum of society. He appeals to the Moral Law as general guidance for dealing with these issues (p. 320). In particular he advocates four ethical principles (formulated by T. L. Beauchamp and J. F. Childress in their book Principles of Biomedical Ethics, 1994) that we might all be able to agree on in making such decisions. They are:
- Respect for autonomy – the principle that a rational individual should be given freedom in personal decision making, without undue outside coercion.
- Justice – the requirement for fair, moral, and impartial treatment of all persons
- Beneficence – the mandate to treat others in their best interest
- Nonmaleficence – "First do no harm" (as in the Hippocratic Oath)
These are good guidelines, though many problems will undoubtedly arise when such general secular ethical principles collide with the demands of specific religious beliefs and cultural practices. When supposedly infallible religious texts become part of the discussion, it makes it almost impossible to seek underlying unifying moral and ethical principles on which to base judgments.
POST SCRIPT: Brace yourself
Matt Taibbi warns that this presidential election is going to be very rough.
April 18, 2008
The changing problems of science and religion
(I will be away on travel this week so will be reposting an old series, edited and updated, that discusses the nature of science and the difference between science and religion. New posts start again on Monday, April 21, 2008.)
In the previous posting, I discussed some of the problems that arise is reconciling science and religion. These problems change with time as our understanding of science changes and the explanatory powers of science encompass more and more phenomena.
For example, in the pre-Copernican era, one could have had a plausible model of god that became much harder to sustain in the light of post-Copernican scientific developments. This was because the universe then was seen as consisting of a spherical Earth located at the center of a finite universe and surrounded by a concentric rotating sphere in which the stars were embedded. (See Thomas Kuhn's The Copernican Revolution for a detailed history.) People thought that the stars were very small objects, and thus the outer sphere containing them could be quite nearby.
In that model, it was possible to think of the heavens as lying beyond this outer sphere and this provided a home for god and angels and so on. There are no major conceptual problems in believing this model. This model enabled people to envision without much difficulty how god could intervene in the events on Earth. All that was required was to imagine god as having pretty much the same powers as human beings did, but just more powerful and extensive. Thus god has more refined senses, sees better, hears better, is more powerful, travels faster, etc. It was not hard to think of god in heaven actually seeing and hearing what was going on Earth, being able to send thunderbolts or other forms of signals from heaven to Earth, or even making a quick trip (either personally or by sending angels) to Earth. Believing that god intervened in everyday events was not that hard to conceive within the framework of a pre-Copernican cosmology.
But Copernicus' introduction of a heliocentric universe, and the more precise astronomical observations made possible by the invention of the telescope caused some serious problems for such early models, although the theological implications seemed to have taken some time to sink in.
As Kuhn points out (on page 193):
When it was taken seriously, Copernicus' proposal raised many gigantic problems for the believing Christian. If, for example, the earth were merely one of six planets, how were the stories of the Fall and of the Salvation, with their immense bearing on Christian life, to be preserved? If there were other bodies essentially like the earth, God's goodness would surely necessitate that they, too, be inhabited. But if there were men on other planets, how could they be descendents of Adam and Eve, and how could they have inherited the original sin, which explains man's otherwise incomprehensible travail on an earth made for him by a good and omnipotent deity? Again, how could men on other planets know of the Savior who opened to them the possibility of eternal life? Or, if the earth is a planet and therefore a celestial body located away from the center of the universe, what becomes of man's intermediate but focal position between the devils and the angels? If the earth, as a planet, participates in the nature of celestial bodies, it cannot be a sink of iniquity from which man will long to escape to the divine purity of the heavens. Nor can the heavens be a suitable abode for God if they participate in the evils and imperfections so clearly visible on a planetary earth. Worst of all, if the universe is infinite, as many of the later Copernicans thought, where can God's Throne be located? In an infinite universe, how is man to find God or God man?
Most of those new problems are metaphysical. The last point mentioned by Kuhn is the one I want to focus on because it represents a physical problem and the one that is of most interest to me as a physicist. If the universe if infinite, then where does god exist? Since telescopes can now observe vast sections of the universe, it strains the imagination to think of god occupying some part of the physical universe because if god is made of the same kinds of stuff as other things in the universe, then how is it that our telescopes and other devices don't detect anything?
I am not sure (not being an expert of the history of theology) but it may be that it was to solve this problem that popular ideas about god being a non-material entity (and hence undetectable by telescopes) who is everywhere began to gain ground. That way, it was possible to overcome the time and space problems associated with having a material god who necessarily has to occupy the same physical space as us.
But this raises yet other problems. If god is non-material and occupying a non-material space that co-exists with our more familiar material world, then how can he/she interact with the material world to influence it? After all, if (say) god intervenes to change the course of natural events, then it must involve changing the behavior of tangible physical objects and this requires the application of forces to those tangible objects, and such forces fall within the realm of the physical world.
One solution is to forego all interventions by god except in the form of changing people's minds, and postulate that human beings possess a mind that is independent of the body, and thus occupies a space similar to or identical with that occupied by god. Thus communication within this 'spirit world' can take place between god and people. Such models allow for the concept of an after-life.
But this just shifts the problem one step away, and does not solve it. Because then we have the problem of understanding the mind-body relationship of each person and this has all the problems associated with the god-people relationship. If the mind exists independently of the body, then where does it exist? If the mind is a non-material entity, then how does it influence the body (which is material)? And so on. Such concerns were articulated by the mathematician-scientist-philosopher Rene Descartes (1596-1650). Note that Descartes posed these concerns after Copernican ideas had taken hold and the potentially vast size of the universe became better appreciated, giving such problems a sense of urgency,
The way that I have formulated these questions obviously reveals my physics background. I treat space and time as meaningful physical entities and so cannot easily absorb platitudinous statements like "god is everywhere" without further exploration as to what that statement actually means. I am guessing that most people do not consciously consider these questions either because they do not occur to them or shy away from them because of the discomfort they can cause.
So how does one resolve all these problems created by the assumption of god's existence in the light of modern scientific knowledge about a vast universe? I think once again people have to resort to Ockham's razor and each person will choose a position that satisfies him or her. I found that using Ockham's razor resulted in my dispensing with the idea of god altogether.
Assuming the existence of god creates a vast number of contradictions and complications that can only be dealt with by pleading ignorance and invoking an inscrutable deity, neither of which is very satisfying.
April 17, 2008
Science, religion, and Ockham's razor
(I will be away on travel this week so will be reposting an old series, edited and updated, that discusses the nature of science and the difference between science and religion. New posts start again on Monday, April 21, 2008.)
A few days ago I was working in my backyard when I noticed that the outdoor thermometer that I had fixed to a fence had disappeared. The mountings were still there but had been pulled away slightly. I thought that maybe the wind had blown it off and so I looked at the ground underneath but the thermometer was not there. There is a bed of pachysandra nearby and I looked nearby in it but no luck. I was baffled.
I pondered the various options for explaining the missing thermometer. One was that the wind had been strong enough to rip the thermometer from its mounting and blow it farther away into the pachysandra. The other was that it had fallen to the ground below and had then been taken away by squirrels or the neighbor's cat. The third was that neighborhood children had borrowed it without permission for some experiment. The fourth was that the International Outdoor Thermometer Cartel (IOTC) had raised the price of these thermometers to such a high value that organized crime gangs were stealing them and selling them on the black market. The fifth option was that aliens had taken it away as a souvenir of their clandestine visit to Earth.
Given these options, I decided that #1 was the most likely one and looked in the pachysandra over a larger area and, sure enough, I found it.
The reason for this anecdote is that it illustrates that I used something that we all use all the time (whether we are consciously aware of it or not), and that is Ockham's razor to make choices among competing theories.
According to the Encyclopedia Brittanica, the principle behind Ockham's razor (also called the law of economy or the law of parsimony) was stated by the scholastic William of Ockham (1285–1347), as "Plurality should not be posited without necessity." The principle is also expressed as "Entities are not to be multiplied beyond necessity." Ockham did not himself use the word 'razor', that was added to his name later by others.
The principle gives precedence to simplicity, but there are two ways it can be used. In the first case (which is more closely aligned with Ockham's intent), it says that you should not postulate more elements for anything other than the minimum required. For example, in the case of my missing thermometer, if I postulated one theory that a cat had taken it and a competing theory was that a cat that had a striped tail and a scar on its forehead had taken it, then in the absence of any extra information, the former theory is to be preferred. The latter theory just adds elements that do not add any necessary information to the explanation. The application of this version of the principle is fairly straightforward. One seeks the smallest subset of elements of a theory that provides an adequate explanation of whatever you are trying to explain.
The more problematic (but common) use of Ockham's razor is when you try and apply it to a situation where there are two competing theories that share either no common elements or there exist at least some necessary elements of one theory that the other does not possess. We commonly interpret Ockham's razor in those situations as requiring us to choose the simpler of the two theories. But simplicity may well lie in the eye of the beholder and it may not be easy to get agreement.
So, for example, in the case of the thermometer that was found some distance away from its mountings, the simpler explanation (for me at least) was that of the wind. If called upon, I could cite Bernoulli's Principle and the laws of motion to support my preference. That explanation is enough to satisfy me.
But this may not be true for someone else. For someone who is a believer in the existence UFOs and space aliens, a theory that alien vandals landed in my garden, tore the thermometer from its moorings, threw it away in the pachysandra and left in their spaceship, might be the "simpler" explanation. After all, it does not involve the use of calculus.
That is exactly the problem in many of the science and religion discussions. Apart from those people who reject science altogether, the integration of science and religion into one coherent philosophical framework becomes one of the most difficult challenges and there is no simple solution to it. And all of us use Ockham's razor to resolve it, even though the results are not the same for everyone.
A belief in the existence of god implies that there must be at least some phenomena caused by the intervention of god that lie outside the purview of science. (I am not considering the point of view that god created the world and its laws in one instant of time long ago and then has had a completely hands-off policy since then.)
For example, Biblical literalists will start with the assumption that the Bible is a historical document and that the events described in it (the world was created in six days and is only 6,000 years old, Joshua caused the Sun to stand still, Noah's flood did occur, etc.) all actually occurred. They will then painstakingly and tortuously try and reinterpret all evidence to be consistent with these axioms. The website Answers in Genesis goes to extraordinary lengths to try and answer questions such as "Where did Cain find his wife?" and "Did dinosaurs live alongside humans?" These are questions that do not trouble anyone who does not treat the Bible as an authoritative source for science and history.
But even those who take the Bible less literally have to confront difficult questions because at some point, the question is going to arise about where you draw the line and ascribe something to the actions of god. Each person will draw the line between god's actions and the actions of natural laws differently, depending on their personal level of comfort with the explanation.
This is something that believers in any theistic religion have to confront. Some will believe that any event that does not have a ready explanation to hand (a death in the family, an escape from injury, an unexpected recovery from a serious illness) are directly due to god's intervention to change the course of events. In order to deal with the existence of evil in the presence of an omnipotent and loving god, believers usually end up having to postulate that god's actions are inscrutable and that we cannot know the answers to at least some of the events that occur in the world.
At the other end, others might believe that god does not actually cause a change in the natural sequence of events but instead exerts his/her influence by working through people. In other words, people are the agents of god's actions and the sole mechanism by which he/she influences events. So people are cured of illnesses because god inspires researchers and physicians, and so on.
There are also an infinite number of intermediate states between those two extremes. For example, people like the biochemist Michael Behe, who is an intelligent design advocate and author of the book Darwin's Black Box, accept natural explanations for everything except for a few selected phenomena at the biochemical level (such as the blood clotting mechanism or the creation of the bacterial flagellum) that he feels are unlikely to have been created by natural processes. (See the New Yorker article by H. Allen Orr for a clear description of what Behe's argument is. Cory also sent me a link to a nice article written by John Rennie, editor of Scientific American, that addresses some of the key points raised by ID advocates.)
Or one can use decide that there is no god (or supernatural entity of any kind), and all that exists is the material world. This is the position of philosophical naturalism or atheism. (I am treating the two terms as effectively synonymous, although professional philosophers might disagree).
So we are left with only Ockham's razor with which to make a decision but in this case, it is a very personal razor whose use will satisfy only us. I personally find that assuming no god exists makes everything simpler and much more meaningful.
But those who are committed to believing in the existence of god despite the lack of evidence for his/her existence will not agree with me that this is the simplest explanation. They will likely say that having an inscrutable god who for some reason allows unspeakable cruelties is a 'simpler' way of understanding the world.
Which position one ends up taking is thus largely determined by deciding which is 'simpler' to believe in, which usually means deciding which belief structure you want to believe in and find personally enriching and meaningful, since there is no unambiguous measure of simplicity for incommensurable theories.
April 16, 2008
Why scientific theories are more than just explanations
(I will be away on travel this week so will be reposting an old series, edited and updated, that discusses the nature of science and the difference between science and religion. New posts start again on Monday, April 21, 2008.)
At its heart, intelligent design creationism (IDC) advocates adopt as their main strategy that of finding phenomena that are not (at least in their eyes) satisfactorily explained by evolutionary theory and arguing that hence natural selection is a failed theory. They say that adding the postulate of an 'intelligent designer' (which is clearly a pseudonym for god) as the cause of these so-called unexplained phenomena means that they are no longer unexplained. This, they claim, makes IDC the better 'explanation'. Some (perhaps for tactical reasons) do not go so far and instead say that it is at least a competing explanation and thus on a par with evolution.
As I discussed in an earlier posting, science does purport to explain things. But a scientific explanation is more than that. Scientific explanations also always carry within themselves the seeds of new predictions, because whenever a scientist claims to explain something using a new theory, the first challenge that is thrown invariably takes the form "Ok, if your theory explains X under these conditions, then it should predict Y under those conditions. Is the prediction confirmed?"
If the prediction Y fails, then the theory is not necessarily rejected forever but the proponent has to work on it some more, explain the failure to predict Y, and come back with an improved theory that makes better predictions.
Even if the prediction Y is borne out, the theory is still not automatically accepted but it gains a little bit of credibility and may succeed in attracting some people to work on it. Theories become part of the scientific consensus when their credibility increases by these means until they are seen by the scientific community as being sufficiently strong and robust that they become the exclusive framework, or 'paradigm', for future investigations.
A scientist who said things like "My new theory explains X but makes no new predictions whatsoever" would be ignored or face ridicule because such theories are easy to manufacture and of no practical use for science. And yet this is precisely the kind of thing that IDC proponents are saying. To see why this cannot be taken seriously, here is something abridged from the book Physics for the Inquiring Mind by Eric Rogers (p. 343-345), written way back in 1960. In it Rogers looks at competing claims for why an object set in motion on a surface eventually comes to rest:
The Demon Theory of Friction
How do you know that it is friction that brings a rolling ball to a stop and not demons? Suppose you answer this, while a neighbor, Faustus, argues for demons. The discussion might run thus:
You: I don't believe in demons.
Faustus: I do.
You: Anyway, I don't see how demons can make friction.
Faustus: They just stand in front of things and push to stop them from moving.
You: I can't see any demons even on the roughest table.
Faustus: They are too small, also transparent.
You: But there is more friction on rough surfaces.
Faustus: More demons.
You: Oil helps.
Faustus: Oil drowns demons.
You: If I polish the table, there is less friction and the ball rolls further.
Faustus: You are wiping the demons off; there are fewer to push.
You: A heavier ball experiences more friction.
Faustus: More demons push it; and it crushes their bones more.
You: If I put a rough brick on the table I can push against friction with more and more force, up to a limit, and the block stays still, with friction just balancing my push.
Faustus: Of course, the demons push just hard enough to stop you moving the brick; but there is a limit to their strength beyond which they collapse.
You: But when I push hard enough and get the brick moving there is friction that drags the brick as it moves along.
Faustus: Yes, once they have collapsed the demons are crushed by the brick. It is their crackling bones that oppose the sliding.
You: I cannot feel them.
Faustus: Rub your finger along the table.
You: Friction follows definite laws. For example, experiment shows that a brick sliding along a table is dragged by friction with a force independent of velocity.
Faustus: Of course, the same number of demons to crush however fast you run over them.
You: If I slide a brick among a table again and again, the friction is the same each time. Demons would be crushed on the first trip.
Faustus: Yes, but they multiply incredibly fast.
You: There are other laws of friction: for example, the drag is proportional to the pressure holding the surfaces together.
Faustus: The demons live in the pores of the surface: more pressure makes more of them rush out and be crushed. Demons act in just the right way to push and drag with the forces you find in your experiments.By this time Faustus' game is clear. Whatever properties you ascribe to friction he will claim, in some form, for demons. At first his demons appear arbitrary and unreliable; but when you produce regular laws of friction he produces a regular sociology of demons. At that point there is a deadlock, with demons and friction serving as alternative names for sets of properties - and each debater is back to his first remark.
Faustus's arguments are just like those of the IDC advocates, and the reason why they are consistently rejected by the scientific community. Scientists ask for more than just explanations from their theories. They also need mechanisms that make predictions. They know that that is the only way to prevent being drowned in an ocean of 'explanations' that are of no practical use whatsoever.
You can't really argue with people like Faustus who are willing to create ad hoc models that have no predictive power. Such explanations as he gives have no value to the practicing scientist. At some point, in order to save your time and your sanity you have to simply walk away and ignore them. This explains why so many scientists refuse to get involved in the IDC battles.
But when you walk away from this kind of fruitless pseudo-debate, you do allow the other side to charge that you are afraid to debate them, at which point, they may jump up and down and shout "See they cannot refute us. We win! We win!", however illogical the charge.
It reminds me of the duel scene in Monty Python and the Holy Grail in which King Arthur chops off the arms and legs of the Black Knight, leaving just his torso and attached head on the ground, totally vanquished. The Black Knight refuses however to concede defeat and offers a compromise: "Oh? All right, we'll call it a draw." When Arthur and his assistant walk away from this offer, the Black Knight starts taunting him saying "Oh. Oh, I see. Running away, eh? You yellow bastards! Come back here and take what's coming to you. I'll bite your legs off!"
You can see the scene from the film here:
The IDC people are the Black Knights of the science-religion debate. Despite their arguments suffering one devastating refutation after another, they think they are invincible because god is on their side, will not concede that they have lost the battle, and refuse to go away. All that they have left is bluster.
April 15, 2008
Why intelligent design creationism is not science
(I will be away on travel this week so will be reposting an old series, edited and updated, that discusses the nature of science and the difference between science and religion. New posts start again on Monday, April 21, 2008.)
In a previous posting, I pointed out that if one looks studies the history of science, all the theories that have been considered to be science are both (1) naturalistic and (2) predictive. Thus these two things constitute necessary conditions for a theory to be considered science.
This is an important fact to realize when so-called intelligent design creationism (IDC) advocates argue that theirs is a 'scientific' theory. If so, the first hurdle IDC must surmount is that it meet both those necessary criteria, if it is to be even eligible to be considered to be science. It has to be emphasized that meeting those conditions is not sufficient for something to be considered science, but the question of sufficiency does not even arise in this case because IDC does not meet either of the two necessary conditions.
I issued this challenge to the IDC proponents when I debated them in Kansas in 2002. I pointed out that nowhere did they provide any kind of mechanism that enabled them to predict anything that anyone could go out and look for. And they still haven't. At its essence, IDC strategy is to (1) point to a few things that they claim evolutionary theory cannot explain; (2) assert that such phenomena have too low a probability to be explained by any naturalistic theory; and (3) draw the conclusion that those phenomena must have been caused by an 'unspecified designer' (with a nudge, nudge, wink, wink to the faithful that this is really god) whose workings are beyond the realm of the natural world explored by science.
Thus they postulate a non-natural cause for those phenomena and cannot predict any thing that any person could go and look for. (This is not surprising. The designer is, for all intents and purposes, a synonym for god and it would be a bit bizarre to our traditional concept of god to think that his/her actions should be as predictable as that of blocks sliding down inclined planes.) When I asked one of the IDC stalwarts (Jonathan Wells) during my visit to Hillsdale College for an IDC prediction, the best he could come up with was that there would be more unexplained phenomena in the future or words to that effect.
But that is hardly what is meant by a scientific prediction. I can make that same kind of vague prediction about any theory, even a commonly accepted scientific one, since no theory ever explains everything. A truly scientific prediction takes the more concrete form: "The theory Z encompassing this range of phenomena predicts that if conditions X are met, then we should see result Y."
IDC advocates know that their model comes nowhere close to meeting this basic condition of science. So they have adopted the strategy of: (1) challenging the naturalism and predictive conditions, arguing that these are not necessary conditions for science and that they have been adopted to specifically and unfairly exclude IDC from science; and (2) tried to create a new definition of science so that IDC can be included. This takes the form of arguing that a scientific theory is one that 'explains' phenomena.
(There are, of course, variations and expansions on these arguments by the various members of the IDC camp but I have tried to reduce it to its skeletal elements. These variations that IDC proponents adopt are designed to blur the issues but are easy to refute. See this cartoon by Tom Tomorrow (thanks to Daniel for the link) and this funny post by Canadian Cynic about the possible consequences of using IDC-type reasoning in other areas of life.)
The rejection by IDC advocates of naturalism and predictivity as necessary conditions for science goes against the history of science. Recall, for example, that in the struggle between the Platonic and Copernican models of the universe, both sides of this debate involved religious believers. But when they tried to explain the motions of the planets, both sides used naturalistic theories. To explain the retrograde motion of Mercury and other seemingly aberrant behavior, they invoked epicycles and the like. They struggled hard to find models that would enable them to predict future motion. They did not invoke god by saying things like "God must be moving the planets backwards on occasion." Or "This seemingly anomalous motion of Mercury is due to god." Such an explanation would not have been of any use to them because allowing god into the picture would preclude the making of predictions.
In fact, the telling piece of evidence that ended the dominance of the geocentric model was that the Rudolphine Tables using Kepler's elliptical orbits and a heliocentric model were far superior to any alternative in predicting planetary motion.
While it may be true that the underlying beliefs that drove people of that time to support the Platonic or Copernican model may have been influenced by their religious outlook, those earlier religious scientists did not seem to invoke god in a piecemeal way, as an explanation for this or that isolated unexplained phenomenon, as is currently done by IDC advocates. Instead they were more concerned with the question of whether the whole structure of the scientific theory was consistent with their understanding of the working of god. In other words, they were debating whether a geocentric model was compatible with their ideas of god's role in the world. They seemed to feel that detailed motions of specific planets, however problematic, were too trivial for them to invoke god as an explanation, although they would probably not have excluded the possibility that god was capable of routinely adjusting the motion of planets.
It may also well be true that some scientists of that time thought that god might be responsible for such things but such speculations were not part of the scientific debate. For example, Newton himself is supposed to have believed that the stability of the solar system (which was an unexplained problem in his day and remained unsolved for about 200 years) was due to god periodically intervening to restore the initial conditions. But these ideas were never part of the scientific consensus. And we can see why. If scientists had said that the stability was due to god and closed down that avenue of research, then scientists would never have solved this important problem by naturalistic means and thus advanced the cause of science. This is why scientists, as a community, never accept non-natural explanations for any phenomena, even though individual scientists may entertain such ideas.
So the attempts by IDC advocates to redefine science to leave out methodological naturalism and predictivity fly completely in the face of the history of science. But worse than that, such a move would result in undermining the very methods that have made science so successful.
In the next posting, I will discuss why just looking for 'good' explanations of scientific phenomena (the definition of science advocated by the IDC people) is not, by itself, a useful exercise for science.
April 14, 2008
What is science?
(I will be away on travel this week so will be reposting an old series, edited and updated, that discusses the nature of science and the difference between science and religion. New posts start again on Monday, April 21, 2008.)
Because of my science training and my interest in its history and philosophy I am sometimes called upon to answer the question "what is science?" Most people think that the answer should be fairly straightforward. After all science is such an important and integral part of our lives that everyone feels that they already know what it is and think that the problem of defining science is purely one of finding the right combination of words that captures their intuitive sense.
But as I said in an earlier previous posting, strictly defining something means having demarcation criteria for it, which involves developing a set of necessary and sufficient conditions, and this is extremely hard to do even for seemingly simple things like (say) defining what a dog is. So it should not be surprising that it may be harder to do for an abstract idea like science.
But just as a small child is able, based on its experience with pets, to distinguish between a dog and a cat without any need for formal demarcation criteria, so can scientists intuitively sense what is science and what is not science, based on the practice of their profession, without any need of a formal definition. So scientists do not, in the normal course of their work, pay much attention to whether they have a formal definition of science. If forced to define science (say for the purpose of writing textbooks) they tend to make up some kind of definition that sort of fits with their experience, but such ad-hoc formulations lack the kind of formal rigor that is strictly required of a philosophically sound demarcation criterion.
The absence of an agreed-upon formal definition of science has not hindered science from progressing rapidly and efficiently. Science marches on, blithely unconcerned about its lack of self-definition. People start worrying about definitions of science mainly in the context of political battles, such as those involving so-called intelligent design creationism (or IDC), because advocates of IDC have been using this lack of a formal definition to try to define science in a self-serving way so that their pet idea can be included as science, and thus taught in schools as part of the science curriculum and as an alternative to evolution.
Having a clear-cut demarcation criterion that defines science and is accepted by all would settle this question of whether IDC is science once and for all. But finding a satisfactory demarcation criterion for science has proven to be remarkably difficult.
To set about trying to find criteria that distinguishes between one class of ideas from another class, we do what we usually do in all such cases, we first set about finding all the unambiguous members of each class and see if we can extract common properties of each class.
In the case of science, we look at all the knowledge that is commonly accepted as science by everyone, and see if we can identify what is common among these areas. For example, I think everyone would agree that the subjects that come under the headings of astronomy, geology, physics, chemistry, and biology, and which are studied by university departments in reputable universities, all come under the heading of science. So any definition of science that excluded any of these areas would be clearly inadequate, just as any definition of 'dog' that excluded a commonly accepted breed would be dismissed as inadequate.
This kind of exercise is exactly we do when trying to define other things, like art (say). Any definition of art that excluded paintings hanging in reputable museums would be considered an inadequate definition.
Similarly, there is a general consensus that astrology, fortune-telling, and the like are not science. Any definition of science that resulted in those topics being considered science would be considered inadequate.
When we look at the history of the topics studied by people in those named disciplines that are commonly accepted as science, the first thing that we notice is that for a theory to be considered scientific it does not have to be true. Newtonian physics is commonly accepted to be scientific, although it is not considered to be universally true anymore. The phlogiston theory of combustion is considered to be scientific though it has long since been overthrown by the oxygen theory. And so on. In fact, since all knowledge is considered to be fallible and liable to change, truth is, in some sense, irrelevant to the question of whether something is scientific or not, because absolute truth cannot be established.
(A caveat: Not all scientists will agree with me on this last point. Some scientists feel that once a theory is shown to be incorrect, it ceases to be part of science, although it remains a part of science history. Some physicists also feel that many of the current theories of (say) sub-atomic particles are unlikely to be ever overthrown and are thus true in some absolute sense. I am not convinced of this. The history of science teaches us that even theories that were considered rock-solid and lasted millennia (such as the geocentric universe) eventually were overthrown.)
But there is a clear pattern that emerges about scientific theories. All the theories that are or have been considered to be science are (1) naturalistic and (2) predictive.
By naturalistic I mean methodological naturalism and not philosophical naturalism. The latter, I argued in an earlier posting where these terms were defined, is irrelevant to science.
By predictive, I mean that all theories that are considered part of science have the quality of having some explicit mechanism or structure that enable the users of these theories to make predictions, of being able to say what one should see if one did some experiment or looked in some place under certain conditions.
Note that these two conditions are just necessary conditions and by themselves are not sufficient. (See this earlier posting for what those conditions mea