Abstract
The principles of ontological parity and ordinality have distinct functions in Buchler's ontology. Ontological parity could be independently subscribed to, whereas ordinality signals the positive conception of the nature of reality as irreducibly complex or indefinitely related, which Buchler's metaphysical system seeks to articulate. Both principles inform Buchler's system, but each has a distinctive function. They are not, I suggest, necessarily at odds with one another, as some critics claim. I do identify several difficulties that follow from (1) the level of generality claimed by Buchler and (2) the claim of irreducible complexity or indefinite relatedness.