Note 281 — Chapter IX · THE VERDICT. (continued 3)

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?