13 Jun 2014 10:28

Reductionism, roughly speaking, is the view that everything in this world is really something else, and that the something else is always in the end unedifying. So lucidly formulated, one can see that this is a luminously true and certain idea. The hope that it could ever bee denied or refuted is absurd. One day, the Second Law of Thermodynamics may seem obsolete; but reductionism will stand for ever. It is important to understand why it is so indubitably true. It is rooted ... not in the nature of things, but in our ideal of explanation. Genuine explanation, not the grunts which pass for such in "common sense", means subsumption under a structure or schema made up of neutral, impersonal elements. In this sense, explanation is always "dehumanising", and inescapably so.
---Ernest Gellner, Legitimation of Belief, p. 107
Are there are any alternatives to it which make any sense whatsoever? --- For instance, the only non-reductionist explanations I can think of are in logic and mathematics, and it's not clear that those are explanations at all. (To be more concrete. If someone asks me, "why is chalk white?" I can give a nice reductionist explanation about the optical properties of calcium carbonate, and the emission and absorption of photons, and rod and cone cells in the eye. If I draw a matrix with the chalk, and someone asks me "why can't I invert it?" the best I can do is say something like "it's a singular matrix." But it's not at all clear that I have said anything new in that case, as opposed to just bringing to mind some parts of the relevant definitions.) --- In any case, I should really like to see so much as a single non-reductionist explanation of something empirical.

Need I add that explanations in ecology, chaos theory, etc., are all impeccably reductionist, whatever some of their well-intentioned practitioner may say?

Correspondence with Danny Yee shows me that I have, as usual, been unclear. When I talk about reductionist explanations, I don't mean uniformly working our way down to the level of sub-atomic wavicles (or whatever), and dismissing everything else as unreal. Much as I respect Democritus, I cannot agree that there is only "atoms and void": I think it obvious to the meanest understanding that there are many other things as well, such as human beings and soccer balls and kittens and forests, which are made up of atoms and void. If one sets about explaining the behavior and properties of these composite things, one can't rest content with "the whole is more than the sum of its parts" (what on Earth does that mean?), or a virtus dormativa, or anything of that sort. One proceeds slowly, piece-meal, and does not attempt to explain even the ricochet of a soccer-ball off a goal-post using Schrödinger's equation. Excessive reduction leads to hypotheses which are neither very useful nor very testable. (I should say that Danny and I are in agreement, at least this far.)

But, you may say, this is not reductionism. Very well then, I am not a reductionist: neither are Richard Dawkins, nor Daniel Dennett, nor Heinz Pagels, nor Steven Weinberg, who all (among others) argue for this position better than I do, and are quite happy calling themselves "reductionists." (Dawkins and Dennett prefer "hierarchical" and "piece-meal" reductionist, respectively.) See also Emergent Properties; Mechanistic Explanations