 A number of other questions about Quantity could be asked. For instance, Aristotle’s treatment of quantity in the Metaphysics includes species not present in his treatment in the Categories (Meta. 1020a7–34), which raises questions as to the extent to which the set of doctrines in the Categories coheres with the doctrines in his other physical and metaphysical works. Furthermore, questions about Aristotle’s views about the nature of some of the species in quantity arise. So, for instance, to what does Aristotle think the species number corresponds? He surely does not think that numbers exist apart from the material world. But then what exactly does Aristotle think a number is? All we get for an answer from the Categories is that number is a discrete quantity. But such an answer hardly provides much of an understanding as to what Aristotle has precisely in mind. Moreover, why does Aristotle include speech as a species in the category of quantity? Speech hardly seems like a natural candidate for this category. Perhaps, Aristotle has in mind the quantities of vowels and syllables of Greek words. But, if anything, speech would seem to be some kind of vocal sound, which arguably is a kind of affection. Each of these questions is interesting and worth pursuing. I shall not, however, offer any answers to them here. Rather, I hope only to have illustrated how deeply intriguing and yet difficult to pin down fully Aristotle’s Categories is.