are extended. But, just because we have set aside the elements, atoms or what not, to which these movements had been affixed, we are no longer dealing with that movement which is the accident of a moving body, with that abstract motion which the mechanician studies and which is nothing, at bottom, but the common measure of concrete movements. How could this abstract motion, which becomes immobility when we alter our point of reference, be the basis of real changes, that is, of changes that are felt? How, composed as it is of a series of instantaneous positions, could it fill a duration of which the parts go over and merge each into the others? Only one hypothesis, then, remains possible; namely, that concrete movement, capable, like consciousness, of prolonging its past into its present, capable, by repeating itself, of engendering sensible qualities, already possesses something akin to conciousness, something akin to sensation. On this theory, it might be this same sensation diluted, spread out over an infinitely larger number of moments, this same sensation quivering, as we have said, like a chrysalis within its envelope. Then a last point would remain to be cleared up: how is the contraction effected,—the contraction no longer of homogeneous movements into distinct qualities, but of changes that are less heterogeneous into changes that are more heterogeneous? But this question is answered by our analysis of concrete perception: this