Dost Thou bid me assent, if any define time to be |motion of a body?| Thou dost not bid me. For that no body is moved, but in time, I hear; this Thou sayest; but that the motion of a body is time, I hear not; Thou sayest it not. For when a body is moved, I by time measure, how long it moveth, from the time it began to move until it left off? And if I did not see whence it began; and it continue to move so that I see not when it ends, I cannot measure, save perchance from the time I began, until I cease to see. And if I look long, I can only pronounce it to be a long time, but not how long; because when we say |how long,| we do it by comparison; as, |this is as long as that,| or |twice so long as that,| or the like. But when we can mark the distances of the places, whence and whither goeth the body moved, or his parts, if it moved as in a lathe, then can we say precisely, in how much time the motion of that body or his part, from this place unto that, was finished. Seeing therefore the motion of a body is one thing, that by which we measure how long it is, another; who sees not, which of the two is rather to be called time? For and if a body be sometimes moved, sometimes stands still, then we measure, not his motion only, but his standing still too by time; and we say, |it stood still, as much as it moved|; or |it stood still twice or thrice so long as it moved|; or any other space which our measuring hath either ascertained, or guessed; more or less, as we use to say. Time then is not the motion of a body.