In his commentary on Aristotle's Metaphysics, Alexander of Aphrodisias quotes from Aristotle's now-lost work On the Ideas -- his account of the arguments offered by Plato for the theory of Forms and his criticisms of those arguments. This paper considers one of these arguments, the Argument from Relatives (ta pros ti). It considers how Plato argued for Forms or Ideas such as the Large Itself, the Just Itself and so on and whether Plato supposed that there were Forms (...) corresponding to sortal terms like Man. (shrink)