a taste for desert landscapes

The Guardian bookshop has a pro-evolution book on offer at the moment, and the first line of the blurb goes like this:

Why Evolution is True focuses on the hard evidence that proves evolution by natural selection to be a fact.

I remarked that I think almost every word in that sentence is misleading, dishonest, wrong, shallow, or just plain stupid.

— To which A.N. Other replied: “Please elaborate”.

— What’s wrong with it? — Let me count the ways… Briefly, to me it looks irredeemably confused between theories, facts, and reasons, and it misguidedly supposes that science is looking for certainty rather than explanations.

To elaborate, I should first make it clear that I think the theory of evolution is a very good theory — it’s so good that I believe it. That is, I think the theory of evolution is true. In other words, I think that in its larger details, it accurately describes evolution, which is a process that actually happened, and is still happening.

I suppose there are alternative ways of understanding “facts”, but the most obvious way is to take a “fact” to be a state of affairs that makes some claim or other true. So if the sentence ‘the cat is on the mat’ is true, what makes it true is the fact that there is a warm, furry, four-legged thing reclining on a inanimate, rectangular, fibrous thing with the word ‘welcome’ written on it.

Similarly, supposing that the theory of evolution is indeed true, we have a theory (i.e. the theory of evolution) and a separate thing, the fact (i.e. the actual process of evolution) that makes it true.

Armed with that uncontentious understanding of “truth” and “fact”, let’s examine the claim made by the blurb:

The first word is ‘why’. This word normally asks for — or provides — a reason, in other words a belief and/or desire that justifies a claim or motivates an action. So a fine title for a book might be Why Everyone Should Believe the Theory of Evolution. But Why Evolution is True is confused on two counts. It seems to suppose that a fact (evolution) is true rather than a theory (the theory of evolution), and it seems to suppose that what makes it true is not a fact but a reason. That has the makings of an epistemological nightmare!

Next, we have ‘hard evidence’. What, I wonder, makes evidence “hard” as opposed to soft? I strongly suspect that this author takes the evidence in question to be a “firm foundation” for evolutionary theory. But really, it is various observational tests and other epistemic “virtues” that count in favour of hypotheses, rather than their being “based on” foundations. The central hypotheses of evolutionary theory are indeed explanatorily powerful, very simple and general, remarkably fecund (in the sense that they prompt fertile new lines of inquiry) and so on. So there is good evidence for believing them. But is this evidence “hard” in the sense of acting as a foundation for the theory, or in the sense of delivering great predictive accuracy? — No! — It’s just about as “soft” as it gets, although there’s a lot of it.

Finally, it is claimed that this supposedly hard evidence “proves” evolution as a fact. The use of the word ‘prove’ here reinforces the sense that the evidence works like axioms supporting a theorem in mathematics. But the real evidence for evolutionary theory is nothing like that — nor does any other branch of science feature that distinctively “mathematical” structure.

I suspect that the reason why the author or publisher stamps his feet by using words like ‘proves’ is that he has completely “missed the point” of science in general. It does not deliver certainty, nor should anyone expect it to. It is a speculative, tentative project whose aim is to draw back the curtain on things we mostly cannot see directly. It is a dizzying, risky attempt to understand nature, not to lock it in a half-Nelson by filing things away under “proved”.

When I first read Wittgenstein, his frequent accusations of ”scientism” irritated me. No more. I now see that the mass psychosis of our current age is a worshipful attitude to people who call themselves “scientists”, but who would not recognize a genuinely scientific explanation if it jumped up and bit them on the bum. It’s probably another tragic consequence of the collapse of religion.