According to evolutionary theories of mind, that we have evolved under certain selective pressures not only causally explains our mental functioning, but in fact is essential to that very functioning. Thus, if an exact duplicate of one of us came into existence at random, with no selection, it would not have a mind. The reason is that components of minds have to have proper functions, and proper functions in us are to be analyzed through natural selection.
Of course, there could be critters whose proper function is to be analyzed in terms of artificial selection, or even in terms of design by an agent. But as it happens, we are not critters like that, says the evolutionary theorist of mind. Nonetheless, it is important that the account of proper function be sufficiently flexible that artificial selection would also be able to give rise to proper function (after all, how would one draw the line between artificial and natural selection, when artificial selectors—say, human breeders—are apt themselves to be a part of nature?). Moreover, typically, the evolutionary analysis of proper function is made flexible enough that agential design gives rise to proper function as well. The basic idea—which is more sophisticated in the newer accounts to avoid counterexample—is that it is a proper function of x to do A if and only if x-type entities tend to do A and x-type entities now exist in part because of having or having had this tendency. Thus, a horse's leg has running fast as one of its proper functions, because horse's legs do tend to run fast, and now exist in part because of having had this tendency. A guided missile has hitting the target as a proper function, because it tends to do that, and guided missiles exist in part because of having this tendency (if they didn't have this tendency, we wouldn't have made them).
Whatever the merits of these kinds of accounts of proper function, I think it is easy to see that such an account will not be satisfactory for philosophy of mind purposes. To see this, consider the following evolutionary scenario (a variant on one that the ancient atomists posited). Let w0 be the actual world. Now consider a world w1, where at at t0 there is one super-powerful alien agent, Patricia, and she has evolved in some way that will not concern us. Suddenly, at t0, a rich infinite variety of full-formed organisms comes into existence, completely at random, scattered throughout an infinity of planets. There are beings like dogheaded men, and beings like mammoths, and beings like modern humans, behaving just like normal humans. On the evolutionary theorist's view, these are all zombies. A minute later, at t1, Patricia instantaneously kills off all the organisms that don't match her selective criteria. Her selective criteria in w1 happen to be exactly the same ones that natural selection implemented in w0 by the year 2009. Poof, go the mammoth-like beings in w1, since natural selection killed them off by 2009 in w0. However, humanoids remain.
At t1, the survivors in w1 have proper functions according to the evolutionary theorist. Moreover, they have the exact same proper functions as their analogues in w0 do, since they were selected for on the basis of exactly the same selective principle. This was a case of artificial selection, granted, but still selection.
But it is absurd that a bunch of zombies would instantaneously become conscious simply because somebody killed off a whole bunch of other zombies. So the evolutionary account of proper function, as applied to the philosophy of mind, is absurd.
Maybe our evolutionary theorist will say: Well, they don't get proper functions immediately. Only the next generation gets them. Selection requires a generation to pass. However, she can only say this if she is willing to say that agency does not give rise to proper function. After all, agency may very well work by generating a lot of items, and then culling the ones that the agent does not want. Pace Plantinga, I do not think it is an absurd thing to say that agency does not give rise to proper function, but historically a lot of evolutionary accounts of proper function were crafted so as to allow for design-based proper functions. Moreover, it would seem absurd to suppose that a robot we directly made couldn't be intelligent at all but its immediate descendant could be.
I think the above shows that we shouldn't take agential design to generate proper function (at least not normally; maybe a supernatural agent could produce teleological facts, but that would be by doing something more than just designing in the way an engineer does), at least not if we want proper function to do something philosophically important for us. Nor do I think should we take evolution to generate proper function (my earlier post on this is particularly relevant here). Unless we are Aristotelians—taking proper function not to be reducible to non-teleological facts—we have no right to proper function. And thus if the philosophy of mind requires proper function, it requires Aristotelian metaphysics.