In his Critique of pure reason Kant discusses two philosophical doctrines of Aristotelian origin: the definition of truth as adaequatio intellectus et rei and the theory of the transcendentals, condensed in the formula quodlibet ens est unum, verum, bonum. The Spanish philosopher Antonio Millán-Puelles has carried out, in two of his books, an examination of the value of this Kantian discussion. The aim of this paper is to comment on Millán- Puelles’ analysis and to complete it in certain points, in order to show its properly philosophical interest and its originality.