Abstract

Quine’s general approach is to treat ontology as a matter of what a theory says there is. This turns ontology into a question of which existential statements are consequences of that theory. This approach is contrasted favourably with the view that takes ontological commitment as a relation to things. However within the broadly Quinean approach we can distinguish different accounts, differing as to the nature of the consequence relation best suited for determining those consequences. It is suggested that Quine’s own narrowly formal account fails. Then a consideration of the necessitation approach championed by Jackson and Lewis shows that it does not do justice to the role of acknowledging consequences in determining rationality. I suggest that an approach which puts a priori consequence as the key relation does a better job. The task of spelling out the nature of a priori consequence is sketched, along with reasons to doubt the adequacy of the double indexing approach to analysing the a priori. The sorts of relations we can stand in to theories which allow us to inherit ontological commitments are touched on with a number of important philosophical strategies for introducing belief-like attitudes which nevertheless avoid ontological commitment.