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The Rationalist Dream Come True
by Joel Marks
Ever since Euclid axiomatized geometry, the dream of philosophy has been to derive all of nature from a set of self-evident truths. From the start the project was dubitable: after all, geometry is about airy abstractions, while nature is made of dirt. You could take any starting point ideas you please and derive a whole world from them, but that world is likely to be fantasy. The peculiar thing about geometry, though, was that it did seem to have some purchase on reality. It is not only in the mind of a mathematician that the interior angles of a triangle add up to 180 degrees, but also on a piece of paper.
Except that… they don’t on the surface of the Earth, whose curvature expands the angles. Ah, but then you can just alter the axioms, as was done for so-called ‘non-Euclidean’ geometries. But you see, there is no guarantee that any geometry you construct will correspond to the real world. The axiomatized systems are like the artist’s palette, from which not just any color will match the pallor of your model’s complexion. The correct color might not even have a popular name: just so, the axioms of a successful system – a geometry that truly describes our world – might not be obvious at all. Parallel lines that meet, anyone (as in Riemannian geometry and Einsteinian cosmology)? Finally, in 1931, Kurt Gödel seemed to put the kibosh on the whole rationalist axiomatization project when he proved his Incompleteness Theorems, which hold that any sufficiently complex system will contain evident truths that are neither axioms nor derivable from axioms of that system.
But a funny thing has happened in recent decades: biology (of all things!) has developed to such a point that philosophers need weep no more. I suppose we could date this development from the publication of E.O. Wilson’s book Sociobiology in 1975, with other landmarks like his On Human Nature, Richard Dawkins’ The Selfish Gene, Robert Wright’s The Moral Animal, and Daniel Dennett’s Darwin’s Dangerous Idea. Diversely presented here is an explanatory paradigm that accounts for all of living nature in its teeming variety and wondrous fitness to circumstances (and which, according to Dennett, may eventually encompass all of non-living nature as well: the universe itself). And it does so on the basis of a single principle, whose truth is not obscure, like E = mc2, but as patent as A = A.
I am referring of course to Darwinian evolution. The central principle seems to be true of necessity: whatever exists had to survive long enough to exist. “It’s that simple,” as the loudspeakers tell me at my local supermarket when advertising their commitment to high quality and low prices. From this principle you can derive everything! Of course you have to think about it: Godlessness is in the details. But there have been enough success stories that one seems justified to be confident the rest will fall into line.
Here is a rough illustration of how this type of explanation works. Everything has been going along swimmingly in your little pond when, by and by, due to climatic change, the ambient temperature exceeds the comfort level of reproduction for most of your fishy fellows. But by random variation, some like it hot; and you just happen to be so constituted as to be one of them. Therefore you and a similarly febrile mate end up populating the pond with your progeny, who all share this trait and hence live to tell this fish tale. (Which is also why they are in trouble come the next ice age… except of course if there happen to be the odd few cold fish who like it that way, who will fill up the pond quick enough.)
A variation: The temperature (range) stays the same, but a cosmic ray or random mutation gives rise to a regular peacock of a fish who sets all the female fishes’ hearts aflutter. Too bad for you: no fun and no future. Another variation: The new generation of peacock fish spend all their time feeding or flaunting, but over time a number of them develop an odd habit of hurling themselves into the jaws of their natural predators, the big mouths. This typically happens after the years of reproduction, however, so the habit continues. It turns out that the pond contains another organism, of microscopic proportion, which usually just floats about waiting for a chance encounter with a big mouth, in whose maw it reproduces. But now that the peacocks have shown up on the scene, a few of the micros, who are inadvertently swept up by them, happen to have the aforementioned effect on elderly peacock fish when they reach their somewhat debilitated brains. This increases the odds that this type of micro will reproduce; hence their numbers increase relative to micros that don’t have it; hence more and more peacock fish are infected with this odd trait.
And so it goes, ad infinitum. What powers it is nothing but the vast variety of differences and changes of organisms and habitats, which diversity is itself brought on by the endless play of cause and effect. Thus has the rationalist dream – that all of nature could be comprehended by thought and reason – become the rationalist reality. It is not that nature consists of mind, as an ‘idealist’ would hold, but that it can be understood by mind. Nor does this deflate one jot our emotional response to the universe due to the loss of mystery. On the contrary, as Dawkins puts it at the end of his magnificent (indeed, amazing) new book The Ancestor’s Tale, in which he leads us on a scientific pilgrimage back to ‘the dawn of evolution’: “If, as returning host, I reflect on the whole pilgrimage... my overwhelming reaction is one of amazement.” (p.613) That the amazement itself can probably be explained by the same scheme is but the crowning touch.
© Joel Marks 2007
Joel Marks is Professor of Philosophy at the University of New Haven in West Haven, Connecticut. More of his essays can be found at http://moralandothermoments.blogspot.com