Aristotle maintains that defining nous requires first defining its activity, which requires first having considered its objects, intelligible beings. This chapter is about the nature of these objects: what about them makes them intelligible? My principal proposals will be that what makes them intelligible is that they are separate or unmixed, and that because, insofar as they are intelligible, they are, in their essence, activity. I am not unaware that this makes it sound as though Aristotle takes intelligibility to consist in some kind of nous. But he himself virtually says as much, when he claims that nous is the form of its objects (lit. εἶδος εἰδῶν); besides it is a result he is committed to by the doctrines that nous is intelligible and that there is something that intelligible objects all are in common; for the alternative, as he himself says, is to suppose that nous “will have something mixed-in, which makes it intelligible just like the rest.” The challenge, then, is not to steer clear of this result, but to make sense of it. My proposal will be that the key lies in realizing that and why Aristotle thinks intelligibility is a creature of nous.