ABSTRACT
This chapter argues that Jacob Klein is right to understand a noetic unit existing in the sensible entity. The year was 1976, and he was writing a dissertation on Aristotle's Metaphysics. For reasons he can no longer recall, he decided to spend the summer in London working at the British Library, then still located in the British Museum. Julia Annas's commentary on Metaphysics M and N had just appeared in the Clarendon Aristotle series, and she had a chance to see her in Oxford. Cassirer traces the development of number from mental acts of abstracting numbers from concrete objects, Mill is as far back as he considers to a fullblown conceptual system in which individual numbers, now thoroughly separated from things, derive their entire meaning from their relations with other numbers and conceptually defined relations between them. It is worth noting that Cassirer has a high regard for the mathematical thought of both Frege and Russell.
