Metaphysics of Species for the Commitment-wary

Abstract

I have argued that Species-as-Individuals (SAI) can be defended only at steep cost. It might, of course, be a cost worth paying. But to decide this we should consider the alternatives. At this point, a defender of SAI is likely to cry in exasperation: What alternatives?! Everything must be either concrete or abstract. There’s no third option. “We can apply the terms ‘class’ and ‘individual’ to all bona fide ontological categories” (Ghiselin 1997, p. 37). Things are, however, a bit more complicated than Ghiselin makes out. In the first place, most philosophers will want to think of classes and individuals as ontological categories, rather than properties of ontological categories. A more reasonable interpretation of Ghiselin’s claim is that any bona fide entity must fit in one ontological category or another—and that there are only two: classes and individuals. While coherent, this latter claim is controversial. Some philosophers have explored ontologies with more than two categories.¹