The sudden rise of a new Republican US presidential candidate — Michele Bachmann, “the thinking man’s Sarah Palin” — has prompted a predictable wave of claims that she is a nutter. She must be a nutter, apparently, because she has very strange views about homosexuality, she claims to have fully reared 23 foster children, and she neither believes in evolution, nor in manmade global warming.
Well, yes, I agree she is a nutter. Her wonky homophobic attitudes and wonky fantasies about being a Mia-Farrow-type “hypermom” point to that. But skepticism about evolution and skepticism about manmade global warming are very different. The first is driven by religious belief, and depends on appeals to authority. The second is driven by deeper doubts about methodology, and depends on a rejection of authority.
Although no one had a full theory of evolution till Darwin described the mechanism of natural selection, most intelligent non-religious thinkers have accepted for centuries that some form of evolution is the only reasonable alternative to the biblical account of creation. And the latter doesn’t really count as an explanation of life and diversity, because the life forms that God is supposed to have created must have existed as ideas in His mind before He made them physical realities. The trouble is, that leaves us with the more intractable problem of explaining the contents of God’s mind, which has to be every bit as complicated and mysterious as the things it designed. So, far from explaining something complicated and mysterious in terms of something less complicated and less mysterious, we instead have to appeal to something even more complicated and more mysterious. That is no explanation! It is so obviously not an explanation that the only obvious alternative — some sort of evolutionary theory — has been the “default” position for centuries.
Darwin’s theory of evolution fits the general pattern of scientific discovery. Something stands in need of explanation, and someone comes up with some hypotheses that explain it. Together, these hypotheses have various observational consequences — in other words, they imply that we will be able to see various things happening — which indeed are actually observed to happen. The theory of evolution departs slightly from the general pattern of science by relying less on testing and more on explanation. But testing and explanation are logically quite similar. In the first case, something has not been seen yet, and we have no reason to expect it. But the theory predicts it, and if it is indeed seen as predicted, the theory passes the test and gives us a reason where formerly we had none. In the second case, something has already been seen, but we don’t understand it — in other words, it surprises us. The theory gives us a reason not to be surprised by it. In both cases, we start off without reasons, and hypotheses supply us with the reasons we were without. In both cases, guesses enable us to “fill in the gaps”.
A lot of Americans say they don’t believe in evolution. Having met a fair number of American students, I’m not sure we should take all such claims at face value. A tongue-in-cheek contrarianism is quite common in America, at least in American universities. Students know they are “supposed to” believe in evolution, by their teachers and the mainstream media, and setting themselves against all that adds a touch of contrarian “spice” to their self-image. So we mustn’t think America is wall-to-wall with people who reject evolution. Having said that, of course many do sincerely reject it. Those that do sincerely reject it are generally very religious. They take the word of the scriptures as authoritative. That is an appeal to authority.
The theory of catastrophic manmade global warming is quite different from Darwin’s theory of evolution. It doesn’t itself explain anything, but instead takes as its starting point an uncontroversial part of mainstream physics (i.e. the greenhouse effect). Using computer modeling, it makes a one-off prediction that we are all headed for catastrophe. That is prediction, but it isn’t prediction used as a means of testing the theory. In fact this theory pretty much dispenses with explanation and testing altogether, substituting instead the common but mistaken idea that empirical knowledge rests on a “foundation” of “data”, as if observation comes first and theoretical knowledge is “based” on it. But that is not the way of science. It is not even the way of most everyday knowledge of the world. Observation suggests hypotheses, and tests hypotheses, but it just cannot imply hypotheses.
So why should anyone believe this body of supposed knowledge that so signally fails to fit the general pattern of scientific discovery? — Because we are “supposed to”. The authorities tell us to. These authorities include pillars of the establishment such as Her Majesty’s government, Her Majesty’s loyal opposition, the BBC, the Archbishop of Canterbury, the Guardian, and the rest of them. But above all we are supposed to believe “the scientists”.
Examine their methodology, and you will see that they are just people who call themselves scientists.