Chatton wades into the debate between Scotus, a realist, and Ockham, a nominalist, most extensively in Lectura d. 2, q. 5, defending Scotus’ position against Ockham’s unrelenting attack contained in the latter’s Ordinatio d. 2, q. 6. We see that Chatton adopts Scotus’ basic picture of the metaphysical structure of substances, both immaterial substances like angels and material substances like human beings, cats, and trees. In each case, the particular entities of a given kind, for instance each and every human being, are constituted by various natures – humanity, animality, etc. – and what Chatton calls an ‘individual property.’ Also known as a haecceity, the individual property of, say Socrates, is what individuates each substantial and accidental nature such that they are Socrates’s humanity, animality, whiteness, etc. and not Plato’s, who has his own individual property that makes his humanity, animality, whiteness. his own. The nature of humanity as such is a repeatable and instantiable property but as individuated, Socrates’s humanity is not; it is utterly individual and singular. Scotus thought, and Chatton emphasizes this in the face of Ockham’s conviction that every thing is radically particular, that natures never exist as such out there in external reality. Natures either exist in extra-mental reality as individuated and singular, Socrates’s humanity and Plato’s humanity each being numerically one and distinct from one another, or natures exist in the mind as universal concepts where they are indeed predicable of many.