April 27, 2009
Skyhooks and cranes-1: Why skyhooks are appealing
I occasionally meet people who, knowing something about my interests with science and religion, say something like "I am not religious but I am skeptical of the theory of evolution." These people are often well-educated but not biologists or archeologists or paleontologists or anthropologists, so it is unlikely that they have done any kind of scholarly study of the evidence in favor of evolution and found it wanting. Their skepticism of evolution seems to spring from a different well.
When questioned, it usually turns out that the major reason for their doubts is that we live in a world that has an amazing array of diverse and complex organisms. If one doesn't closely into the science and mathematics of evolutionary theory, it can seem quite incredible that all this could have emerged by purely natural causes. So for some people, skepticism about evolution arises purely from a sense, a gut feeling if you will, that it is highly unlikely that life arose in the unguided way that evolution proposes. Just last week I had a discussion with a professor of chemistry who argued in precisely this way, that he could not imagine that all this could have come about without some kind of guiding intelligence, and what could that be but a supernatural agency of some kind?
I have argued before that evolution by natural selection, though unguided, is very far from something that happens purely by chance. While it is chance that produces the variations, the process of natural selection is highly focused. Furthermore, people's intuitions about probability are notoriously poor, and people should be wary of placing too much weight on them.
The other major source of discomfort is that people cannot properly conceive of very long timescales, especially the hundreds of millions of years that are involved in evolutionary processes. Things that are unlikely over shorter time periods can become likely, even inevitable, if you wait long enough, but people have no real feel for that. For example, we all know that the chance of winning a big lottery prize is very small. But if I were willing to play for a very, very long time, the probability of my winning becomes very high, almost inevitable. But of course, the amount I would have bet would be almost certainly be much more than my winnings and I would be long since dead anyway, so the whole exercise would be pointless. But our tendency is to take the probability over our short lifetimes, and erroneously assume it remains the same over very long time scales.
But even allowing for that, there is something strange about the theory of evolution being singled out for skepticism. After all, all manner of small probabilities and long time scales are involved in the Big Bang theory, involving the way that the primordial matter coalesced to form the stars, planetary systems, and galaxies. Why aren't people similarly skeptical about how the Earth and our Solar system came into being? Some religious fundamentalists, of course, do argue that god created everything and reject pretty much all of science, but I am not talking about them. I am talking about people who have no problem accepting scientific theories of how the entire universe came to be, but yet remain unconvinced that scientific theories can explain how all of life came into being.
There is another possible reason for this focused skepticism against evolution. The Big Bang is a spectacular thing to visualize. There is a magnificence to it that is commensurate with the importance we attach to something that happened at the very beginning of time. But the theory of evolution is the very opposite, saying that life in all its grandeur came about very slowly as a result of a vast number of tiny little plodding steps, each too small to observe. There is no arresting visual image that we can seize upon.
Daniel Dennett's book Darwin's Dangerous Idea (1995) says that the basic idea of Darwin's theory, that everything is a product of an algorithmic process, a simple set of rules mindlessly applied, is what many people find hard to accept.
Among the controversies that swirl around us, most if not all consist of different challenges to Darwin's claim that he can take us all the way to here (the wonderful world we inhabit) from there (the world of chaos or utter undesignedness) in the time available without invoking anything beyond the mindless mechanism of the algorithmic processes he proposed. (p. 74)
As a result of this skepticism, people have consistently, over time, invoked what Dennett calls skyhooks as explanations. A skyhook is defined as an "imaginary contrivance for attachment to the sky" that can be used for lifting things easily. The skyhook concept is similar to the deus ex machina ("god from a machine") literary device used by inferior Greek dramatists to suddenly swoop down and lift their characters out of a tight spot. So a skyhook is basically a mysterious and advanced mechanism that can be invoked as an explanation. The existence of skyhooks as explanatory mechanism leads naturally to an acceptance of the existence of a designer, since someone had to have created the skyhook.
The search for skyhooks has historically taken many forms. In the early days, skyhooks were used to explain the appearance of every species. This was the theory of 'special creation', popular up to Darwin's day, where god (the ultimate skyhook) created species to fit into the various ecological niches. As time went by and science explained more and more of what was previously inexplicable, the number of skyhooks needed as explanatory devices has decreased, but never gone away.
The 'God of the Gaps' that I have written about earlier is a manifestation of this desire for skyhooks.
The idea of skyhooks is seductive and is what draws many of us in to believing in a creator, especially when we are young. It is a form of magical thinking that all young children find attractive and which is what makes believing in a god easy.
But why do people continue to feel the need for skyhooks as adults when there are other good explanations?
Next: Replacing skyhooks with cranes.
POST SCRIPT: The appeal of skyhooks for children
In this interview with Jonathan Miller, Richard Dawkins says that as a boy he accepted the need for skyhooks for the creation of life, before he discovered that the theory of evolution solved the problem, and the sense of intellectual freedom and liberation that it generated.