[281] We say movement, not motion, though we know that these two words are considered as synonymous. Motion corresponds to the Latin motio, whilst movement corresponds to the Latin motus. Motio means the motive action—that is, motion properly—both as proceeding actively from the agent, and as passively received in the patient; motus, on the contrary, signifies the result of the motio given and received; and this result is movement. As in philosophy we have to distinguish between action and its result, we must keep up a distinction between the words also. Very probably movement and motion would never have been accepted as synonymous, had the verb to move exclusively retained its original active signification; but, as people imagined that movement was a kind of action, they thought it right to say not only that the horse moves the cart, but also that the cart moves, instead of saying that it is moved. Even Newton has been so misled by the popular use of this verb as to write more than once corpus movet, instead of corpus movetur. It was but natural that "movement," too, should be transformed into "motion." Are we too late to restore to these two words their distinct meanings?
[282] See Kleutgen, The Old Philosophy, diss. 2, c. 4.
[283] We cannot here explain the different kinds of identity; but we hope we shall take up this matter in one of our future articles.
[284] The same distinction may be very properly expressed by saying that the carving is materially terminated to the marble, and formally to the statue.
[285] Dublin Review, January, 1873, pp. 70, 71.
[286] Nomen naturæ videtur significare essentiam rei secundum quod habet ordinem vel ordinationem ad propriam operationem rei; quum nulla res propria destituatur operatione. Quidditatis vero nomen sumitur ex hoc quod per definitionem significatur. Sed essentia dicitur secundum quod per eam et in ea res habet esse.—S. Thomas, De Ente et Essentia, c. 1.
[287] Summa Theol., p. 1, q. 14, a. 8.
[288] Esse est perfectissimum omnium; comparatur enim ad omnia ut actus; nihil enim habet actualitatem nisi in quantum est; unde ipsum esse est actualitas omnium rerum, et etiam ipsarum formarum; unde non comparatur ad alia sicut recipiens ad receptum, sed magis sicut receptum ad recipiens. Quum enim dico esse hominis, vel equi, vel cujuscumque alterius, ipsum esse consideratur ut formale et receptum, non autem ut illud cui competit esse.—Summa Theol., p. 1, q. 4, a. 1.