perception and memory a difference of degree—perceptions being then supposed to throw memoriesBut memory is radically different from perception. The past is powerless; the present is sensori-motor, and therefore active. back into the past, and thus to reserve to themselves the present simply because right is might. But there is much more between past and present than a mere difference of degree. My present is that which interests me, which lives for me, and, in a word, that which summons me to action; whereas my past is essentially powerless. We must dwell further on this point. By contrasting it with present perception we shall better understand the nature of what we call 'pure memory.'
For we should endeavour in vain to characterize the memory of a past state unless we began by denning the concrete note, accepted by consciousness, of present reality. What is, for me, the present moment? The essence of time is that it goes by; time already gone by is the past, and we call the present the instant in which it goes by. But there can be no question here of a mathematical instant. No doubt there is an ideal present—a pure conception, the indivisible limit which separates past from future. But the real, concrete, live present—that of which I speak when I speak of my present perception—that present necessarily occupies a duration. Where then is this duration placed? Is it on the hither or on the further side of the mathematical point which I determine ideally when I think of the
