You can’t make sense of anything without a little priming of the conceptual pump. We are born with an innate natural logic that allows us to think about our observations and draw lessons from them, as well as with a capacity to model a Euclidian space (which is why non-Euclidian geometries are counter-intuitive). — Olivier5
We've all been saying things at least a little like this in this thread. I'm not sure there's much alternative, but it also makes me a little uncomfortable.
Suppose I ask, how can a child learn to speak her native language? One answer is: the ability to learn a language is a gift from God. Maybe I find this unsatisfactory, so I keep asking. Another answer is: it is a gift from Darwin, i.e., it's how our species has evolved. But that says nothing at all: however we are is however our species evolved. Since we can demonstrably learn languages, we must have so evolved.
In the period of classic British Empiricism, the options were: (a) it's a gift from God; (b) I made it myself. We didn't have a natural process that could fill the role of the Great Bestower, though of course Hume, he of the preternatural insight, would drop a remark here and there that seems eerily to anticipate the theory of evolution by natural selection. If there is a spirit of empiricism, it's related to this:
The method of "postulating" what we want has many advantages; they are the same as the advantages of theft over honest toil. — Russell
The honest toil of empiricism is to explain how we could have the conceptual apparatus we have -- objects and causes and all the rest -- without just stealing it from the gods like Prometheus. The updated version of rationalism (if we may speak this way) is just to get whatever you need from Darwin's Emporium.
Unfortunately, the middle ground is somewhat unsatisfactory: to justify, in the sense of "rationalize", reliance on evolution, we tell just-so stories of the fitness value of this and that, to make it plausible that the invisible hand would have selected for the traits we need to postulate. We can be sophisticated about this too: we can argue that what we think of as an innate ability to do such-and-such, where this seems an unlikely candidate for providing a survival benefit, is actually the repurposing of an ability originally "selected for" for quite different reasons. I like those stories, but if they're not testable, they're not hypotheses they're just stories.
Honest toil then, under this paradigm, would be restricting yourself to claims you can test. We're scientists after all. Thus if you want to claim, we can do A because there's a clearish survival value to being able to do B (which we can't test, that part remains a story), and A can borrow the mechanism that Bs, you want to test whether people who can't do A also can't do B. Neurobiologists can do some stuff like that with lesion studies, for instance: see whether people known to be unable to A turn out to be unable to B. Psychologists can also try to design experiments to test whether performing A-like tasks is related to performing B-like tasks. There's at least something like honest toil going on here.
What are the philosophers doing while all this is going on? There are always chunks of early modern philosophy, Hume being a pretty good example, that I find a bit tedious because they look a lot like armchair psychology, and we have the real thing now. I don't need Hume to figure out how memory works, say; my tax dollars are doing that, right? If we decide our role as philosophers is to "check up on" scientists, keep them honest, make sure their theories are conceptually up to snuff, we often look a bit ridiculous, like Jerry Fodor insisting that the way far too many biologists talk about evolution is insidiously circular. Mostly, they don't need us for that.
It's tempting to think the role of philosophy is to provide some goals, figure out what needs explaining. I've been tempted now and then to think of philosophy as in fact a sort of (armchair, but maybe it needn't be so) social science, a social science of reasoning. But that turns out to be economics. Kahneman and Tversky, for instance, show pretty definitively, it seems to me, that you needn't waste my tax dollars looking for the brain mechanisms that allow us innately to understand probabilities, because we don't. We suck big time at probabilistic reasoning.
What then is the role of philosophy? We can restrict ourselves to understanding the workings of System 2 -- finding our way around the conceptual apparatus we are just presented with by System 1, we know not how nor for what reasons. I like that well enough; that might be a descriptive metaphysics of the sort Strawson (and, I understand, Collingwood, and kind of everybody) advocated. But it's not clear to me, if we're going to let evolutionary psychology and cognitive science have their say, what a doctrine like empiricism has to offer. What's the point?