What these points suggest, then, is that the most promising way to
develop an analysis of content in terms of function would bring it much
closer to functionalismin the philosophy of mind than is generally recog-
nised. Functionalists think that mental states are to be individuated in
terms of their normal causal role, orfunctionin cognition. Teleo-seman-
ticists think that the contents of mental states are to be individuated by
their distinctivefunctions(normally historical, or evolutionary). But if, as
we have suggested, the latter view is best developed in terms of an a-
historical, contemporary, notion of function, then the two positions will
become much harder to tell apart. It may be, indeed, that teleo-semantics,
properly understood, is a variety of functional-role semantics – on which
see the discussions in section 4 below.
3.5 A-historical functions revisitedIf teleo-semantics is to employ a notion of function which isnotevolution-
ary, then how are we to answer the attendant charges of arbitrariness and
observer-relativity? One possible route is that sketched by Fodor, and
discussed brieXy above, in terms of evolution under counterfactual scen-
arios. For it is, surely, an objective matter of fact whether or not the frog’s
motion-detectors would have evolved and been sustained in a variety of
counterfactual environments. So, one way to objectify what the frog’s
motion-detector does for the frog (that is, its contemporary function) is to
cash it in terms of the range of counterfactual circumstances in which that
detector would have enhanced survival and/or reproductive success.
Another way to rebut the charge of arbitrariness, is to point out that
functions understood in terms of beneWcial contributions to some wider
system can be perfectly objective, provided that the system in question is a
natural kind, whose processes are governed bycausal laws. So provided
that the mind is a natural kind, in the way that psychology takes for
granted, and provided that the various psychological transitions into
which contents can enter are lawful (again, as psychology supposes), then
there can be no principled objection to the use of the notion offunction
within the psychological systemin characterising the contents of our inten-
tional states. Or so, at any rate, it seems to us.
But how, on this approach, are we to distinguish between the eVects of a
mental state which are its functions, and those which are not? We think this
will have to be done in terms of the eVects of the state which partly explain
the continued operations of its containing-system – function-eVects are
those eVects which form part of theexplanationof the operations of the
wider containing-system. Compare: the function of the heart, now, is to
pump blood (whether or not it ever evolved to do that) andnotto cause a
Teleo-semantics 175