Recently somebody challenged me to give an account for why I think things like cats are substances, and why rocks are not, after having agreed with me that we must admit there to be substances in the world in principle. I don’t know that I had thought about this before being thus challenged, but here were some of the arguments I gave.
1) Autobiographical/Theological argument
I noted that in my own history I had come to believe in the substance-accident distinction when I started to take seriously debates between some protestants like Lutherans and Catholics, when they argued about consubstantiation and transubstantiation in regards to the Eucharist. When I came to understand these positions as intelligible given the substance-accident distinction I became persuaded that the better theological arguments were on the side of Transubstantiation. This of course informed my view of what things were substances, since I came to believe, especially as a Catholic, that instances of ‘bread-ness’ and instances of ‘wine-ness’ could always be ostensibly picked out as substances. So, I suppose I could argue that every reason I have for thinking that Catholicism is true is a reason to think that at least bread and wine are substances.
I argued that there are some things which we cannot conceive of at all without conceiving of them as substances, the most obvious example being the self or soul. I think it is impossible for me to apprehend myself as anything other than a substance. Some other things may be like this if they exist at all, like angels, or even like God (since we must conceive of God as some discrete thing with an essence, even though we must say that he is a substance by analogy, and we don’t mean to say that he is a substance in a univocal sense).
3) Kantian Argument
In the Critique of the Power of Judgment Kant argues at great length that given the constitution of our cognitive faculties it isn’t possible for us to make sense of the world except by interpreting it teleologically. In particular we can’t do ‘biology’ without being able to differentiate organisms from non-organisms, but the only way to conceive of the difference is to recognize that an organism is something all of whose parts are organized according to the logic of some end or ‘telos’. If this is true, then it isn’t possible to conceive of any living thing without conceiving of it as having a teleological cause. If this is true then, I argued, it makes sense to recognize an organism to have a substantial form, but where there is a substantial form there is a substance, ergo all living things have to be admitted to be substances.
4) Epistemological argument
I took the Kantian argument and made it more modest by arguing that if we are naturally inclined to think of some things like animals as being organisms with teleological causes, and we can’t conceive of them as being other than substances (or even if we are more naturally inclined to think of them as substances), then perhaps our belief that some cat is a substance is properly basic. A properly basic belief is a belief which we are within our rational rights to believe apart from any evidence or argument, and which we are irrational to disbelieve in in the absence of any defeater which doesn’t itself admit of a defeater (a defeater without a defeater-defeater). If due to the constitution of our cognitive faculties we are naturally inclined to make sense of the world by recognizing that animals and perhaps some other things which seem to have essences are substances then, in the absence of some defeater for that belief, we should accept it.
Those are the arguments which I offered for thinking that cats and dogs are substances, but that rocks and mountains aren’t. I thought I’d blog those arguments to keep some kind of record, and to easily refer anybody if they were interested in reviewing the arguments I presented.