On the last day of a recent conference on the philosophy of biology, an eminent scholar pointed out that no one had yet uttered the R word. He wondered aloud whether the long struggle over reductionism had finally passed, and whether we could move on now please?
The reductionism/anti-reductionism debate is over. I mean, reductionism will always have its defenders – there is no position so hopeless that someone won’t defend it. But serious debate is over. It’s over because reductionism is useless – in the literal, practical sense, it’s useless. You can’t do anything with reductionism.
Ok, what do I mean by that? For the purposes of this post, let’s take reductionism to mean the following:
Everything in the world is nothing more than the sum of its smallest parts.
If you prefer, you could think of it instead about the way we understand everything in the world, but the result will be the same. Either way it is a useless position, because we simply cannot deal with the world in terms of its smallest parts, not all the time.
When confronted with this fairly obvious fact, philosophers will usually say something like “well yes, but in principle…” But principles are supposed to be our basis for activity. If a principle is utterly useless, even misleading for us, then it will be rejected. Reductionism is on the same footing as its opposite, the claim that everything in the world is fundamentally unified, that all is one. In some sense of ‘true’, that may be true. But you can’t use it as a basis for reason and action. Because life depends on chopping up the world into bits, we reject the idea that ‘all is one’ just by living. Similarly, our lives can’t function if we always and only treat the world as made up of quarks or whatever. So forget about reductionism. It’s over.
SMBC explained the situation clearly enough:
But I think there is still some work to be done in explaining, as the title of this post says, what it was. Why did people find the idea of the world-as-just-its-parts so compelling? Some even took it to be essential to scientific thinking, a mandatory prerequisite. Why?
I want to suggest that the actual prerequisite for scientific thinking is the analytic imperative. But being analytic isn’t the same as reducing something to its smallest parts. It just means not explaining the parts of a system in terms of the whole thing. So if I’m being analytic, I can’t explain the movement of a single bird by citing the movement of the flock it flies with, taken as a whole. I have to do it in terms of the local interactions between birds. For example, I can only cite things that my particular bird can see or hear. Or if I want to explain why a single rabbit was eaten by a particular fox, I can’t do it by citing the rising population of foxes. The whole population didn’t eat my particular rabbit, some specific fox did. That is holistic reasoning, explaining by embedding something in its context. If I want to be analytic, I have to explain the rabbit-level event at the level of rabbits, not some higher level like populations. But as long as I’m not explaining by citing the context, it doesn’t matter what level the explanation is pitched at. You can be perfectly analytic about big macroscopic things like organisms, carburetors and planets.
So what I’m suggesting is that people have confused the imperative to treat things categorically and in isolation from their context with the requirement that we always break things up into their smallest parts. Reductionism would then be a kind of mistaken reification of this methodological principle into a supposed metaphysical reality. You can see how that would be a tempting shift to make: the society I’m born in is my context, but to analytically (scientifically) explain my behaviour, you should look for the specific local influences that made me turn out the way I did. You have to find the things that actually impinged on my person, because the society I’m in is, from the perspective of me as individual, my context. But if we take some bit of my brain as the thing-to-be-explained, then my body as a whole becomes the context. Me as an individual is now the thing that cannot be dealt with analytically – you have to find the specific electro-chemical forces that are acting on that bit of my brain to explain it scientifically. If you follow this pattern, it looks like the only thing that won’t be a context for something is whatever the smallest bits are.
But as I said before, you can be analytic at any level. The imperative to be analytic which I think motivates science does not require that you should always only explain things at the lowest mereological level possible. But thinking that it does, I claim motivated reductionism.