I foolishly allowed myself to sidetrack the discussion of my own recent post
on these two major philosophical alternatives (nominalism and realism) into a conversation with Lou Jost on the TOE itself. I blame the fact that I was preparing the piece on neutralism and adaptationism, which nudged me out of philosophy mode. Not that the discussion hasn’t been interesting, even useful, in itself, but it has perhaps prevented the theists here from grappling with the important issues of the nominalist-realist question. So I want to spend just a few more words on it before moving on to another significant philosophical issue in a different post.
I pointed out in the previous column that Darwin’s evolution, and modern thinking generally, has tended to assume a nominalist position (that universal categories don’t truly exist) without necessarily realising it. Continua, especially gradualist evolutionary continua, are assumed not just in biology but everywhere. That’s partly because evolution has become such a pervasive meta-narrative in everything from morality to universes. Everything once considered discrete and specific has become an arbitrarily-divided spectrum, whether that be correct grammar or gender.
At the same time this is inconsistent because, in evolution for instance, universal categories such as taxonomic levels are most often treated as if they are real, as in the concept of nested heirarchies. This ought not to surprise us given our previous examination of final causation, which we found to be denied under naturalism even whilst it is extensively employed in discussing function and so on. Scientific medicine, for example, would be a dead duck if it had no concept of “normal function” to which patients can be restored: without the “ought” of final causation, there could be no therapeutics.
Medical “normality” also implies the reality of universals (the philosophical realism we have been discussing) as well as of final causation. Normality implies there is a standard from which the sick person deviates. Since nobody is “normal” in every respect, the goal at which medicine aims is a non-material ideal, a universal human form.
Universals are even broader than this, though. Philosophers argue about whether mathematics is a merely human construct, or a reality “out there”. There can be no doubt that to the working scientist it is the latter – mathematics is the language of science, and the validation of its universal truth (which is why biology suffers from physics envy!). But mathematics of any sort is nothing but the manipulation of non-physical universals. Nobody can put the number 2 (or any other number) in a bottle. But if the whole human race died, would the ratio of a circle’s circumference to its diameter cease to be π?
To deny universals, then, may be a nice intellectual conceit, but like denying consciousness or free-will it is impracticable (did you hear, by the way, about determinist Jerry Coyne’s recent complaint that Daniel Dennett had been “unnecessarily” rude? Priceless). Accepting realism in theory doesn’t necessarily guarantee that there are such things as natural forms – man, archaeopteryx, insect, animal etc – but it does mean there is no valid reason to deny them philosophically because they are immaterial (you just have to deny materialism, logically). As far as facts can determine theory, as opposed to theory’s tendency to filter facts, which Merv and I have also been discussing, the data ought to give us some guidance.
Without pretending to be initiating a serious research program, let me hint at the kind of things the acceptance of universal forms in biology might predict, which could be investigated. One might find, for example, that forms were very resistant to fundamental change, until at some point there was a quantum event and theropod reptile, for example, became bird very suddenly. This would help explain the universality of stasis followed by entirely new forms in the fossil record. Yet this would not necessarily preclude genomic change occurring in the gradual way suggested by genetic studies (and especially near-neutral change). This kind of notion was perhaps in Eldredge and Gould’s minds (following Futuyma) in reviewing punctuated equilibrium theory in 1993:
…morphological change may accumulate anywhere along the geological trajectory of the species. But unless that change be “locked up” by acquisition of reproductive isolation (that is, speciation) it cannot persist or accumulate and must be washed out during the complexity of interdigitation through time among varying populations of a species. Thus, species are not special because their origin permits a unique moment for instigating change, but because they provide the only mechanism for protecting change.
Let me give a (limited) analogy. Because I am a doctor, let us say, my library consists largely of medical texts. But for whatever reason the shelves begin to accumulate music scores, perhaps, or theological tomes, or books about evolution. Yet I remain a doctor. But at some point, some crisis occurs and I decide, or am forced, to give up medicine. Perhaps I instead become a musician, or a pastor – or worst of all, a blogger on science and faith – and the relevant accumulated information comes into its own. I may even begin to get rid of the medical books. But the library did not make me what I am – that was some different process of “speciation”, and of quite a different order to the ongoing process of filling and emptying bookshelves.
You may note that the variation in my books has relatively little to do with the “origin of the species,” though it’s clearly not irrelevant: it would be odd if my shelves had only works on the theatre in any of my incarnations. It would certainly be of interest to know why I had acquired the particular books I had ahead of a career change: would it be distinguishable from random accumulation of junk before my new status emerged?
If, in a directed theistic evolution framework, my job-change is equivalent to God’s endowment of new substantial form, the nature of the mechanisms involved are of considerable importance. Would Gould’s accelerated gradualism answer the turn? Perhaps, but so far as I can see he was, in punctuated equilbria theory, offering a mechanism of default, assuming the truth and sufficiency of Darwinian selection. Some quite different process or processes might be involved, maybe even saltational, perhaps even “miraculous” in the loose non-Thomistic sense of bypassing secondary causation.
But Darwinian nominalism it wouldn’t be.