"Thanks for the question, especially because it made me consider something I hadn't thought about distinctly. Wouldn't it have to be that primary substances are 'theoretical substances'? Though it's difficult to conceive of a 'this man' without his accidents, if a first substance were to include the accidents, then wouldn't an accidental change, by that conception, actually be a substantial change? I mean, if a primary substance includes the accidents, then a change in the accidents would make the 'this man' now a different 'this man'. For example, if Socrates as a primary substance includes the color of his hair, then wouldn't dying his hair make him a new instance of man?"In my informal polling, that's a typical response. I find that people have not thought clearly about this; yet, when the distinction I raised is posed to them, then they are compelled to say that a primary substance in the Categories is 'an instance of a nature' (as I put it), not a commonsense 'thing'.
What's interesting about an 'instance of a nature', is that, as the quotation above notes, it would lack definite determination of its matter. An instance of human nature would surely be an instance of a soul-with-body, and yet the body would have to be conceived--somehow--as not having a definite size. One would be tempted to say that an 'instance of human nature' was somehow simply a form, that it did not involve matter (on the grounds that matter had to be definite).
Far from this being an objection, I find this difficulty promising as regards interpretation, because it shows that a consideration of the relation of form to matter in primary substances would follow naturally, and almost inevitably, from the very conception of a primary substance understood as an 'instance of a nature'. Think of a primary substance as human nature without accidents, and then inevitably one wants to know how this human nature could involve matter (the body) if at all.
I think it's possible to show that various passages in the Categories require that primary substances be 'theoretical substances'. I'll try to post more on this.
27 April 2006
Posted by Michael Pakaluk at 22:40