continuous measure to measure it, the result would be that extension itself would need measure, so that movement, being measured, may have a quantity which is determined by that of the thing according to which it is measured. Consequently, under this hypothesis, time would be the number of the extension which follows movement, and not extension itself which follows movement. NOR CAN TIME BE A NUMBERED NUMBER (AS ARISTOTLE CLAIMED[452]). What is this number? Is it composed of unities? How does it measure? That would still have to be explained. Now let us suppose that we had discovered how it measures; we would still not have discovered the time that measures, but a time that was such or such an amount. Now that is not the same thing as time; there is a difference between time and some particular quantity of time. Before asserting that time has such or such a quantity, we have to discover the nature of that which has that quantity. We may grant that time is the number which measures movement, while remaining exterior thereto, as "ten" is in "ten horses" without being conceived with them (as Aristotle claimed, that it was not a numbering, but a numbered number). But in this case, we still have to discover the nature of this number that, before numbering, is what it is, as would be "ten" considered in itself.[454] It may be said that it is that number which, by following number, measures according to the priority and posteriority of that movement.[452] Nor do we yet perceive the nature of that number which measures by priority and posteriority. In any case, whatever measures by priority or posteriority, or by a present moment,[455] or by anything else, certainly does measure according to time. Thus this number (?) which measures movement according to priority or posteriority, must touch time, and, to measure movement, be related thereto. Prior and posterior necessarily designate either different parts of space, as for instance the beginning of a stadium, or parts of time. What is called priority is time that ends with the present; what is called posteriority, is the time that begins at the present. Time therefore is something different from the number that measures movement according to priority or posteriority,--I do not say, any kind of movement, but still regular movement. Besides, why should we have time by applying number either to what measures, or to what is measured? For in this case these two may be identical. If movement exist along with the priority and posteriority which relate thereto, why will we not have time without number? This would amount to saying that extension has such a quantity only in case of the existence of somebody who recognizes that it possesses that quantity. Since (Aristotle[456]) says that time is infinite, and that it is such effectually, how can it contain number without our taking a portion of time to measure it? From that would result that time existed before it was measured.