I'm traveling with my family, going out on a boat on the Delaware River tonight with all of my mother's sobrinos, but can't resist a nice basic question.
Billie Pritchett asks, "Do you think intentional states are natural kinds?" I think that an underlying kind of big question is what "natural kinds" are, I for one don't know, Aristotle thought that individual things were primary being and that natural kinds were ineliminable categories of those, species being his paradigm example. Plato thought that logical relations, such as are described in mathematical proofs, were "universals," which were the-most-interesting-being, anyway, so far as he was concerned. I think that this metaphysical discussion lies at the heart of functionalism and in general for the philosophy of mind. In fact my interest in metaphysics grew out of my interest in the metaphysics of mind. If, in addition to the existential fact that something exists rather than nothing, it is a different (contingent) fact that the universe is formally organized, if there are two existential questions instead of one, then "materialism" is false. Progress is to see that on this view the mind/body problem is not a particular problem in metaphysics, rather it is just an instance of the more general metaphysical problem. That looks like a little bit of resolution for the mind/body problem, at least as to the metaphysics of intentionality.
So getting more focused on your question, it is my view (the short answer is) that intentional states are ineliminable. But what are they? (You see that metaphysics is a matter of taking your assertions seriously.) My (admittedly circular) claim is that something is a person to the extent that it takes intentional predicates (a jargon way of saying that we use belief/desire psychology to explain and predict its' behavior). It looks to me that humans, some (actually I think many) non-human animals, possible aliens and possible artifacts can all be (equally) persons, so I conclude that intentional predicates aren't tied to any specific matter or even any specific kind of organization of matter (note that the problem of phenomenal properties requires a whole separate treatment here).
I think that intentional descriptions are descriptions of relations between the person and the environment. This is the connection between my views and behaviorism, also "wide-content" (externalist) accounts, and of course my interest in Wittgenstein. I don't know if relations are properties ("relational properties"), maybe not (John Heil says no). Certainly the whole discussion of "properties" is just as inchoate as the discussion of "natural kinds."