 Now Aristotle, in the two last books of his Metaphysics, had forcefully repudiated the Platonic notion of some such ideal existence of numbers and their principles, and if Aristotle were right, the entire Platonic edifice would have been undermined. Roughly, it was Aristotle’s view, expressed repeatedly in the corpus, that mathematical entities such as numbers or geometrical figures are not themselves substances, that is, basic realities, at all, as these later Platonists required. They are derivative existences, in the sense that the mathematician’s mind in knowing them conceives of them as if they were substances, by looking at the physical world in an abstract way. In other words, mathematical entities do not at all exist independently or prior to the objects they are the number or figures of, but are only hypostatizations of aspects of such objects. In books Mu and Nu he amplifies this view with a searing attack on the early Platonists’ conception of mathematics and their theory of Forms.