  Unlike many of his contemporaries, Aquinas did not compose a commentary on Categories. Nevertheless, there are plenty of references to categories scattered throughout his writings. Two texts are particularly important: one from his Commentary on Aristotle's “Metaphysics,” the other from his Commentary on Aristotle's “Physics” (Met., V. lect. 9; nn. 889–91, Phys. III, lect. 5, nn. 310–20). These texts are important for understanding two aspects of Aquinas' view, the derivation of the categories from modes of predication and the isomorphism between language, thought, and reality.