Genealogical Reasoning

October 13, 2013 § 1 Comment


darwinThe Origin of Species by Means of Natural Selection (Darwin, Charles)

The Origin of Species is an interesting book. It is very rare to come across someone who hasn’t heard of it, or who isn’t strongly convinced of its truth or falsehood. It is even rarer to meet someone who has actually read it.

Like a fecund fish, Darwin’s book has spawned thousands of books, articles, films, lectures and papers both in support and in refutation of it, and these in turn have been quoted and twisted in a thousand ways by their successors; each replication carries a slight tweak to its message, and what we call Darwinism today is just a collection of his original ideas that mutated and survived.

I don’t have an awful lot of clever things to say about the book that haven’t been said before. Actually, I don’t have too many clever things to say about it that HAVE been said before, either. Biology, Zoology, Botany – these have never been my thing since high school, not after that time I was brutally subjected, without the least bit of warning, to the diagram of a toad’s alimentary canal. I still wake up from time to time in a cold sweat, screaming o my eyes my eyes.

OK, here’s one. After reading Darwin, I am fine with the teaching of evolution along with creationism in schools in some of the more religious fundamentalist parts of the world, and with evolution being taught as ‘only a theory’ and along with criticism in others. In fact, I am convinced that it is the only logical way to teach evolution.

If you feel uncomfortable with that, let me tell you that there is a lot to feel uncomfortable about with evolutionary biology. For instance, what exactly is a species? Apparently, no one definition is accepted by all naturalists. There are at least two schools of thought in the matter – taxonomic (involving a set of resemblances) and reproductive (involves interbreeding capability). Neither is satisfactory, and both have exceptions. What precisely makes us accept a Chihuahua and a St. Bernard as variations of a single species, but be equally confident that a lion and a tiger belong to two different species? As Darwin puts it, every species is connected to every other species through a ‘chain of affinities’, some relating to form, others to function, breeding habits, food preferences or survival strategies. The classification into species and variations is not inherent, it is just a matter of linguistic convenience. To paraphrase Judge Potter Stewart of the US Supreme Court, we know a species when we see it. We will disagree with one another a million times, but broadly we will all agree, without agreeing on a single definition, that a poodle is completely different from a Siberian tiger (hint: only one of these reacts well to petting).

Liger_couple

Are these tigers or lions? Neither: they are ligers in a Korean zoo. On no account must you pet them. (Pic courtesy Wikimedia)

I suppose the question is, if we are unable to articulate, in thirty words or less, exactly what constitutes a species, how sure can we be about the origin of species? Darwin’s theory is pitted against others involving, for instance, a grey-bearded (or blue-skinned) man in the clouds. Can he prove his case? Darwin spends 400 pages making his argument patiently, peppering his text with hundreds of descriptions from the animal and plant kingdom; each example is equally persuasive to the open-minded, without ever amounting to proof in the Euclidean sense. He leaves us with no doubt that his theory would satisfactorily explain what we see around us; indeed, that it is a better explanation than any other scientific theory we can think of. Sadly, a creation myth involving a whimsical, inscrutable god can also explain reality. Explanation is not the same as scientific proof.

The fault, of course, lies, not with Darwin, but with our vain quest for clarity in definitions and deductive proof in real-world matters. Darwin felt that the biggest reason for opposition to his theory was that we are not equipped to detect change when it occurs slowly, over millennia. Thomas Kuhn thought the biggest objection to Darwin is that we are not equipped to understand the concept of change without intentionality, without a ‘goal-directed process’. But I think the biggest stumbling-block is because we have no intuitive grasp of how logic, language, data and proof work in the real world.

We – even we, in the 21st century – are held captive by a reductionist, linear, Platonic picture of the world, a model that is consistent with the way WE design things, and with the way a human-like intelligence would have designed the universe. Our instincts for data are poor; we expect lines to be straight, curves to be smooth, edges to be sharp, discontinuities to be absent, and we expect truth to be binary. This sort of data isn’t really found in the world. What we do find, when we look carefully, are blurry edges, jagged lines, clusters of data points with gaps in between, and more than fifty shades of grey. All good scientific education, in final analysis, involves training in consciously overriding our flawed instincts, in redefining our concept of perfection, and above all, in accepting that since nothing can be proved, inductive reasoning using empirical data is all we have at our disposal. Our only hope is to come up with theories that fit the data, and to keep tinkering with the theory as new information becomes available. And the truth of a theory has only one meaning: that it does a more persuasive job than competing theories, especially to an unbiased audience.

So yes: the theory of evolution is ONLY a theory. Deal with it. It is the best one we’ve got, but it is ridiculous to expect anything more. If we don’t keep constantly challenging it with criticism, and we suppress its competitors, how will we ever refine it? How will we get closer to the truth? Certainly not by pretending that it is an unquestionable revelation or universal law.

Let them teach creationism, intelligent design and evolution in schools, I say. By resisting attempts to put evolution up for the Pepsi challenge for persuasive theories, Dawkins and company are taking a rather un-Darwinian stance, and yielding the moral high road to the religious nuts. They should merely insist, after Sagan, on the instillation of a truly open, skeptical mind before any of these theories is taught.

More than anyone else, Darwin’s supporters should know that in the marketplace for theories, truth is determined not by fiat but by persuasion, and persuasion not by proof but by data fit; and the only law is survival of the best fit.

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§ One Response to Genealogical Reasoning

  • A 'Slight' Problem says:

    Well, I notice one problem here. You said “Let them teach creationism, intelligent design and evolution in schools,” but have you ever heard of pastafarianism? Well, I mean…

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