16. If it be urged that Motion is but imperfect Act, there would be no objection to giving priority to Act and subordinating to it Motion with its imperfection as a species: Act would thus be predicated of Motion, but with the qualification "imperfect."
Motion is thought of as imperfect, not because it is not an Act, but because, entirely an Act, it yet entails repetition [lacks finality]. It repeats, not in order that it may achieve actuality- it is already actual- but that it may attain a goal distinct from itself and posterior: it is not the motion itself that is then consummated but the result at which it aims. Walking is walking from the outset; when one should traverse a racecourse but has not yet done so, the deficiency lies not in the walking- not in the motion- but in the amount of walking accomplished; no matter what the amount, it is walking and motion already: a moving man has motion and a cutter cuts before there is any question of Quantity. And just as we can speak of Act without implying time, so we can of Motion, except in the sense of motion over a defined area; Act is timeless, and so is Motion pure and simple.
Are we told that Motion is necessarily in time, inasmuch as it involves continuity? But, at this, sight, never ceasing to see, will also be continuous and in time. Our critic, it is true, may find support in that principle of proportion which states that you may make a division of no matter what motion, and find that neither the motion nor its duration has any beginning but that the division may be continued indefinitely in the direction of the motion's origin: this would mean that a motion just begun has been in progress from an infinity of time, that it is infinite as regards its beginning.
Such then is the result of separating Act from Motion: Act, we aver, is timeless; yet we are forced to maintain not only that time is necessary to quantitative motion, but, unreservedly, that Motion is quantitative in its very nature; though indeed, if it were a case of motion occupying a day or some other quantity of time, the exponents of this view would be the first to admit that Quantity is present to Motion only by way of accident.
In sum, just as Act is timeless, so there is no reason why Motion also should not primarily be timeless, time attaching to it only in so far as it happens to have such and such an extension.
Timeless change is sanctioned in the expression, "as if change could not take place all at once"; if then change is timeless, why not Motion also?- Change, be it noted, is here distinguished from the result of change, the result being unnecessary to establish the change itself.