  Aristotle, e.g., gives an exemplary treatment of the relation between the concepts of ‘being’ and ‘the one’ in the fourth book of his Metaphysics, where he explains that just as being is said in many ways, so also the one; consequently, these notions share the same nature (phusis), while differing qua concept (logos). (Aristotle, Metaph. IV, c. 2, 1003 b 23–4) In the tenth book of the Metaphysics, he explains that the proper meaning of ‘one’ is ‘indivisible’, such that to be one is to be indivisible. (Arist., Metaph. X, c. 1, 1052 b 16.) This model of pairing co-extensionality to intensional difference was to provide the basic framework for a doctrine of the transcendentals. Aristotle’s indications of a focal meaning of being, which reduces the homonymy of the term in such a way as to safeguard the unity of the subject of metaphysics and its possibility as a science (Arist., Metaph. IV, c. 2, 1003 a 32 sqq.), were the starting-point for the medieval reflection on analogy as a mode of predication especially applying to transgeneric terms (cf. the entry on  medieval theories of Analogy). Other important texts in the corpus aristotelicum address the question of truth and the question of goodness. Aristotle’s different assertions on the issue of truth confronted the Middle Ages with a tension. On the one hand, Aristotle asserted that each thing is related to truth in the same way as it is to being; on the other hand, Aristotle excluded being-as-true from the consideration of metaphysics, since it is only a kind of intra-mental being. (Arist., Metaph. II, c. 1, 9993 b 30; Metaph. VI, c. 4, 1027 b 17 sqq.) In his critique of Plato’s Idea of the Good, finally, Aristotle asserts that the good is said in as many ways as being, and hence falls short of the univocity proper to a Platonic idea. (Arist., Eth. Nic. I, c. 4, 1096 a 12 sqq.)