Pharyngula

Nicholas Wade has a very peculiar review of Richard Dawkins’ book, The Greatest Show on Earth, in the NY Times Review of Books. It’s strange because it is a positive review which strongly agrees with Dawkins’ position on the central importance of the theory of evolution in biology in the first half…but the second half is a jaw-droppingly stupid attack on a small point in the book. Wade has a very absolutist and wrong view of the definitions of some terms, and he goes on and on, whining about a topic that he doesn’t understand himself.

There is one point on which I believe Dawkins gets tripped up by his zeal. To refute the creationists, who like to dismiss evolution as “just a theory,” he keeps insisting that evolution is an undeniable fact. A moment’s reflection reveals the problem: we don’t speak of Darwin’s fact of evolution. So is evolution a fact or a theory? On this question, Dawkins, to use an English expression, gets his knickers in a twist.

Oh, man. Wade has really waded into it. This is a subject that has been amply discussed and explained and expounded upon, and I’m surprised that Wade is not only unfamiliar with it, but has thrown away half of his review in a misbegotten error of his own devising. Take it away, Stephen J. Gould:

In the American vernacular, “theory” often means “imperfect fact”—part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess. Thus the power of the creationist argument: evolution is “only” a theory and intense debate now rages about many aspects of the theory. If evolution is worse than a fact, and scientists can’t even make up their minds about the theory, then what confidence can we have in it? Indeed, President Reagan echoed this argument before an evangelical group in Dallas when he said (in what I devoutly hope was campaign rhetoric): “Well, it is a theory. It is a scientific theory only, and it has in recent years been challenged in the world of science–that is, not believed in the scientific community to be as infallible as it once was.”

Well evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world’s data. Theories are structures of ideas that explain and interpret facts. Facts don’t go away when scientists debate rival theories to explain them. Einstein’s theory of gravitation replaced Newton’s in this century, but apples didn’t suspend themselves in midair, pending the outcome. And humans evolved from ape-like ancestors whether they did so by Darwin’s proposed mechanism or by some other yet to be discovered.

Moreover, “fact” doesn’t mean “absolute certainty”; there ain’t no such animal in an exciting and complex world. The final proofs of logic and mathematics flow deductively from stated premises and achieve certainty only because they are not about the empirical world. Evolutionists make no claim for perpetual truth, though creationists often do (and then attack us falsely for a style of argument that they themselves favor). In science “fact” can only mean “confirmed to such a degree that it would be perverse to withhold provisional consent.” I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms.

Evolutionists have been very clear about this distinction of fact and theory from the very beginning, if only because we have always acknowledged how far we are from completely understanding the mechanisms (theory) by which evolution (fact) occurred. Darwin continually emphasized the difference between his two great and separate accomplishments: establishing the fact of evolution, and proposing a theory–natural selection–to explain the mechanism of evolution.

If he’d just written that one little paragraph, it would have been mildly embarrassing for him…but he just keeps stuffing his foot down his throat. It’s a good thing he keeps his pants on to hide the spectacle of his shoe poking out of his butt.

He [Dawkins] seems to have little appreciation for the cognitive structure of science. Philosophers of science, who are the arbiters of such issues, say science consists largely of facts, laws and theories. The facts are the facts, the laws summarize the regularities in the facts, and the theories explain the laws. Evolution can fall into only of of these categories, and it’s a theory.

Whoa. Scientists everywhere are doing a spit-take at those words. Philosophers, sweet as they may be, are most definitely not the “arbiters” of the cognitive structure of science. They are more like interested spectators, running alongside the locomotive of science, playing catch-up in order to figure out what it is doing, and occasionally shouting words of advice to the engineer, who might sometimes nod in interested agreement but is more likely to shrug and ignore the wacky academics with all the longwinded discourses. Personally, I think the philosophy of science is interesting stuff, and can surprise me with insights, but science is a much more pragmatic operation that doesn’t do a lot of self-reflection.

As for his definitions…sorry, but these ideas simply do not fit into the tidy pigeonholes Mr Wade wants to make for them. Evolution is both a fact and a theory. Trying to cram it into one category does violence to both evolution and his cognitive roll-top desk.

And Wade goes on with more! Here’s where we really need philosophers; they could have much more fun shredding the blithe assumptions Wade flings about.

Other systems of thought, like religion, are founded on immutable dogma, whereas science changes to accommodate new knowledge. So what part of science is it that changes during intellectual revolutions? Not the facts, one hopes, or the laws. It’s the highest level elements in the cognitive structure—the theories—that are sacrificed when fundamental change is needed. Ptolemaic theory yielded when astronomers found that Copernicus’s better explained the observations; Newton’s theory of gravitation turned out to be a special case of Einstein’s.

If a theory by nature is liable to change, it cannot be considered absolutely true. A theory, however strongly you believe in it, inherently holds a small question mark. The minute you erase the question mark, you’ve got yourself a dogma.

I don’t even like his dig at religion. There’s a funny thing about religious dogma: it evolves. It changes slowly, usually, and it’s not on the basis of reason or evidence, but more often to bend to popular expediency — I’d agree that it isn’t knowledge that changes it, but the utility of accommodating a human institution to popular perception.

I kind of agree with the general statement that facts won’t change (but as I’ll say below, the facts do shift as they are argued over), but it is possible to change the conceptual framework, the theories, we use to integrate a collection of facts into a useful model in our brains. It is entirely possible for a new model to emerge that does a better job of explaining the history of life on earth someday. After all, it’s already happened, and look, Darwin’s theory still remained a fact!

Darwin’s theory was expanded and replace roughly 70-75 years ago, with the incorporation of the science of genetics into that framework. Darwin was working with a seriously flawed idea of heredity, and all his ideas about the transmission of traits were wrong. Pangenesis was completely scrapped and replaced with Mendelian and population genetics. I can’t imagine a more radical change than that happening any time in the future — we have a solid grip on the rules of heredity now, and what we expect is refinement and the addition of details.

But notice that what happened was a reversal of Wade’s claim. A massive bolus of ‘facts’ were inserted into the theory, but the core of the theory itself, the idea that species changed over time driven by forces of selection, remained. Why? BECAUSE THAT IS ALSO A FACT. We have piled evidence high that shows the earth is old, there have been a succession of forms, that the properties of populations change from generation to generation, that all the diverse forms of life on earth are linked by molecular relationships that fit nicely into a tree of descent. A subsidiary assumption that generations changed by the transmission of acquired characters was discarded, but the big picture was unchanged…and was actually made sharper and stronger.

Any future hypothetical theory that is a better model must incorporate these facts of evolution. It’s one of the reasons creationists aren’t doing science, because they are compelled by ideology to reject the evidence. There will be no theory that denies that human beings are apes and the children of apes, no matter how objectionable creationists find that, because that is a fact. We’ll argue over the mechanisms, whether it was selection-driven or mostly chance divergence, whether group selection played a role, over which fossil fits most closely to the main path of the population that led to us, etc., etc., etc., but the fact of our ape ancestry and nature is established.

One more quibble: Wade insists that every theory must retain that little question mark of doubt, and that is true. However, it also holds true for the facts of science; we can have a fair amount of confidence in the data, but no one considers a published result to be unquestionable. It happens all the time that different labs will wrestle over the data, and the interpretation of the data. It’s one of the factors that drives science, that we work hard to confirm and disconfirm everything. What you’ll actually find when you look at the daily routine of science is that the theories are generally stable and are not strongly questioned — it takes such a massive amount of contradicting data to overthrow a theory that it’s hardly likely that your average individual or research group can demolish a major theory like evolution, or cell theory — and most of the haggling and conflict is over the day-to-day details. You know, that stuff that Wade would try to stuff in his pigeon hole labeled “facts”.

Wade concludes his little diversion into fantasy philosophy with a strange dig at Dawkins that suggests he doesn’t like his book much after all.

He [Dawkins] has become the Savonarola of science, condemning the doubters of evolution as “history-deniers” who are “worse than ignorant” and “deluded to the point of perversity. This is not the language of science, or civility. Creationists insist evolution is only a theory, Dawkins that it is only a fact. Neither claim is correct.

True, neither is crorrect…but then, I guarantee you that Dawkins does not consider evolution to be “only a fact.” Only someone who had not read his books with comprehension could come away with this freakish idea that Dawkins is unaware of the “cognitive structure of science.”

I agree that Dawkins’ words are relatively uncivil, but I’d argue that they’re too civil, and that we need more incivility. Wade does not seem to agree that creationists deny the depth of human history (I don’t understand how he could find fault with the FACT that believing the world is 6000 years old requires blindness to 13 billion years worth of time), or that by promoting false beliefs about our origins they are not merely passively unaware, but are malevolently ignorant, or that using Gould’s definition of a fact, they are in denial “to such a degree that it would be perverse to withhold provisional consent.” Those are the facts that Mr Wade claims to be able to recognize, but ignores in this case.

I also will not accept sad tut-tutting over a lack of civility when Wade so obliviously compares Richard Dawkins to Savonarola. Savonarola? Really? You compare a gentlemanly scholar who writes books to oppose the rising tide of lunacy in the world to a book-burning puritanical fanatic who opposed the Renaissance and sought the death of homosexuals??

Hypocrite.