Evolutionary theories of mind

An evolutionary theory of mind is not just a theory that minds have in fact evolved. Rather, it is a theory that it is essential to mindedness that one be the product of selection (natural or artificial). For instance, one may be an evolutionary theorist of mind because one thinks that intentionality must be understood in evolutionary terms, or because one is a functionalist and thinks that the notion of "proper function" that functionalism needs must be grounded in selective facts, or because one thinks that mental states have normative conditions (e.g., "neural state n is a believing that p only if it is the case that n should occur only if p"). An evolutionary theorist of mind is already willing to bite quite a bullet. Take Davidson's swampman: lightning strikes a swamp, and an exact physical duplicate of Davidson by chance comes out. Since there was no selection, the swampman is not a person, though he is exactly like Davidson physically. Of course if one were a dualist, one wouldn't be surprised by this, since the swampman could differ from Davidson in respect of soul, but the evolutionary theorist of mind doesn't believe in souls. The evolutionary theorist of mind is willing to bite the bullet on the swampman.

Here is an argument against evolutionary theories of mind. As it stands it is an argument against theories on which selection is metaphysically necessary for mindedness, though one might be able to do more with the argument. Moreover, the argument may well apply to other evolutionary analyses of concepts.

The argument is a reductio. Start with the following two theses:

1. (Evolutionary theory of mind.) If none of the physical entities existing in a spacetime region U are the products of selection, there are no physical minds in U.
2. (Almost global supervenience of physical minds.) Suppose worlds w₁ and w₂ are exact physical duplicates, except in an impotent region R of spacetime. Then w₁ contains a physical mind outside of R if and only if w₂ contains a physical mind outside of R.

Here, a "physical mind" is a mind entirely constituted or implemented by a purely physical system. A region R of spacetime is "impotent" provided that no event or substance in R can affect anything outside R.

Now for our clever construction. Imagine a world w₁ which contains a planet much like earth, where history looks pretty much like it looks on earth, and which also contains a Great Grazing Ground (GGG), which is an infinite (we only need: potentially infinite) impotent region. Moreover, by a strange law of nature, or maybe the activity of some swampaliens, whenever an organism on earth is about to die, it gets hyperspatially and instantaneously transported to the GGG, and a fake corpse, which is an exact duplicate of what its real corpse would have been, gets instantaneously put in its place on earth. (I will call it "earth" for convenience but I shan't worry about its numerical identity with our world's earth.) Furthermore, there is no life or intelligence outside of earth and the GGG. Moreover, the organism dies as soon as it arrives in the GGG.

Our world's earth has minds, and the earth in w₁ has a history that is just about the same. The only difference is that all the deaths of organisms occur not on earth but in the GGG, because they get transported there before death. But this does not affect any selective facts. Thus, the evolutionary theorist of mind should say that the situation in w₁'s earth is similar enough to that on our earth that we should say that w₁'s earth contains minds.[note 1]

The hard work is now done. For imagine a world that is exactly like w₁ outside of the GGG, but inside the GGG, immortal and ever-reproducing aliens rescue each organism on arrival, fixing it so it doesn't die, and even make the organism capable of reproduction again. Furthermore, they do the same for the organism's descendants in the GGG. The GGG is a place of infinite (at least potentially) resources, with everybody having immortality and reproduction, with the aliens shifting organisms further and further out to ensure their survival.

Now in w₂, there is no selection: Nobody ever dies or ceases to reproduce.[note 2] Thus, by (1), there are no physical minds outside the GGG in w₂—all the earthly critters are zombies. But by (2) there are physical minds outside the GGG in w₂, because w₂ is an exact duplicate of w₁ outside of the GGG. Hence we have absurdity.

Suppose our evolutionary theorist of mind denies (2). Then we have the following absurdity: It is up to the aliens in the GGG to determine whether or not there are physical minds outside the GGG, by deciding whether to rescue the almost dead organisms that pop into the GGG. But how can beings in an impotent region bring about that there are, or are not, physical minds outside that region? That would be worse than magic (magic is presumably causal).

Furthermore, while the numerical identities of the organisms on earth in w₁ and w₂ might depend on their history, they surely do not depend on what happens in the GGG, since the GGG is impotent. So we may actually suppose that the earthly organisms are numerically the same between w₁ and w₂. Thus, outside the GGG, w₁ and w₂ are exactly the same physically, and have exactly the organisms, but some of these very same organisms (say, Fred or Martha) have physical minds in w₁ and do not have physical minds in w₂.

This is truly absurd. Hence, evolutionary theories of mind should be rejected.[note 3]