  The doctrine of the transcendentals of Thomas Aquinas (1224/5–1274) answers to the question of how an addition to being as ‘first known’ is possible. Aquinas’ solution is that such an addition is possible as the explication of a mode of being that is not yet said by ‘being’ itself: either through a special mode of being, i.e. one of the categories, which contract ‘being’ in their own way, or through a general mode of being, i.e., one of the transcendentals, the addition of which does not yield such a contraction. The basic text De ver. 1.1 explains that the expressed mode of being pertains to every being in itself or in relation to something else. If it pertains to every being in itself, it can either be said positively, i.e. the essence indicated by ‘thing’ (res), or negatively, and that is the ‘indivision’ expressed by ‘one’. If it pertains to every being in relation to something else, it can express either the difference between beings, which is indicated by ‘something’ (aliquid), or their conformity. Since the soul is “in a sense all things”, it is suited to conform to every being. A being either conforms to the soul’s cognitive faculty, which is expressed by ‘true’, or to the appetitive faculty, which is expressed by ‘good’. Aquinas declares ‘being in general’ (ens commune) to be the subject of metaphysics and God to be the principle of this subject (In Metaph., prooem.). Parallel to this restriction of the subject of metaphysics to created being, there is a restriction of the first object of the intellect to the ‘quiddity of material things’ or to ‘being and the true as found in material things’. Reflection on the relation between God and ‘being in general’, which leads Aquinas to present the transcendentals as divine names, and thus to integrate the Platonic and Aristotelian traditions of reflection on ‘being’, ‘one’, ‘true’, and ‘good’, gives rise to the influential doctrine of the analogical predication of the transcendental terms. As stated in the treatise on natural law, the transcendentals ‘being’ (ens) and ‘good’ serve as the foundation of the principles of theoretical and practical reason (S.th. I-II. 94.2).