Note (return) — Chapter XII
Reading edition
2. The Relation of Actuality to Potentiality is a causal Relation.--A thing which is endued with a simple capacity of being may nevertheless not actually exist, and a thing may have a capacity of being and really exist. Since this is the case, there must ensue between non-being and real being some such principle as energy, in order to account for the transition or change. 733 Energy has here some analogy to motion, though it must not be confounded with motion. Now you can not predicate either motion or energy of things which are not. The moment energy is added to them they are. This transition from potentiality to actuality must be through the medium of such principles as propension or free will, because propension or free will possess in themselves the power of originating motion in other things. 734