Confessions

³¹ Do you command that I should assent, if any one should say that time is “the motion of a body?” Thou dost not command me. For I hear that no body is moved but in time. This You say; but that the very motion of a body is time, I hear not; You say it not. For when a body is moved, I by time measure how long it may be moving from the time in which it began to be moved till it left off. And if I saw not whence it began, and it continued to be moved, so that I see not when it leaves off, I cannot measure unless, perchance, from the time I began until I cease to see.

But if I look long, I only proclaim that the time is long, but not how long it may be because when we say, “How long,” we speak by comparison, as, “This is as long as that,” or, “This is double as long as that,” or any other thing of the kind. But if we were able to note down the distances of places whence and whither comes the body which is moved, or its parts, if it moved as in a wheel, we can say in how much time the motion of the body or its part, from this place unto that, was performed.

Since, then, the motion of a body is one thing, that by which we measure how long it is another, who cannot see which of these is rather to be called time? For, although a body be sometimes moved, sometimes stand still, we measure not its motion only, but also its standing still, by time; and we say, “It stood still as much as it moved;” or, “It stood still twice or thrice as long as it moved;” and if any other space which our measuring has either determined or imagined, more or less, as we are accustomed to say. Time, therefore, is not the motion of a body.