Abstract

‘Second substances’ are Aristotle’s species and genera that reveal the general nature of a thing. Sortals correspond to the most specific, least abstract of these, normally thought of as ‘the’ kind to which a thing belongs. I argue against a common view that artifact terms such as ‘clock’ or ‘pen’ are suitable as sortals and for their being regarded as more like genera. If we can individuate clocks and pens as we do trees and rocks, by a combination of sortal plus ostension, then we must use more specific sortals which indicate the structures by virtue of which the objects perform the functions of clocks or pens. Functions by themselves do not supply the identity conditions of sortals. Similar reasoning supports Wiggins’ view that ‘the kind’ to which we belong is our biological species, not the purely functional kind of being a person.