In a lovely recent paper, Andrew Bailey has argued for the priority principle, that we think our thoughts not derivatively from another entity's thinking them--for instance, we don't think our thoughts derivatively from a brain's thinking them, or from a soul's thinking them, or a temporal part's thinking them, etc. I think this is all correct, but it seems to me that arguments of this sort don't go as far as they at first sight seem (this isn't a disagreement with anything Bailey writes).
For it has long appeared to me that the philosopher who is inclined to say that our thinking is derivative from the activity of a proper part of us should deny that the relevant activity of the proper part is thinking. Instead, there is some activity of the proper part which we might call "thinking*", and our thinking is derivative from the part's thinking*. For instance, a materialist might say that our brains think* (and analogously believe*, choose*, etc.), and that to think is to be a maximal organic whole that has a part that thinks*. This seems exactly right. For even if materialism is true, our brains don't think, but we think with our brains. And what our brains do when we think with them isn't thinking, and the materialist shouldn't say it is. (Likewise, when I nail something with a hammer, it is I who nail and not the hammer that nails. Nonetheless, the hammer does something which we can call nailing*, and I nail with a hammer if and only if I stand in the right kind of complex relationship to a hammer's nailing*.)
Once we see things this way, it unfortunately undercuts various arguments that otherwise I would be quite fond of. For instance, Trenton Merricks has a wonderfully clever argument against temporal parts on the grounds that if I have many temporal parts, then I don't know my age, since most of my present temporal parts are younger than me, and yet they think the same thoughts about age as I do. But wonderful as this argument is, and correct as its conclusion is (I don't have any proper temporal parts), the temporal part theorist should (though generally doesn't) say that my proper temporal parts have no opinions as to age, but only opinions*.
Could one strengthen Bailey's priority principle and say that my mental properties are fundamental? That's too strong. Plausibly some mental properties are not fundamental but are grounded in others. Maybe, though, we can say that some mental property is fundamental? That sounds right to me, but it's hard to argue for.