  According to Scotus, neither the logician nor the metaphysician is capable of showing that there are ten categories. There are in fact ten categories, but any attempt to prove that there are only ten is faulty. In his Questions on the “Metaphysics,” he puts it thus: “The various ways for showing the sufficiency of the categories [so far] all seem to err in two ways” (Scotus 1997, V, q. 5–6, n. 73). The first error consists in the attempt to try to prove that there are ten and only ten categories, for such a proof does just the opposite. According to Scotus, purported demonstrations of ten categories rely upon an initial division of predication into two basic classes: predicates that indicate a “being in itself” and predicates that indicate a “being not in itself.” But this implies that there are only two ultimate genera of being, not ten. Indeed, if one were to accept that the modes of predication and the modes of being correspond to each other, as those who try to derive the number of categories from the modes of predication do, then one must conclude that there are only two categories––substance and accident, respectively––not ten. For the two most basic kinds of predication are either “being in a subject” or “not being in a subject.”