impregnated with memory-images, nothing survived from the past, then we should have “pure” perception, not coloured by anything in the individual’s past history, and so a kind of impersonal perception.  However unreal it may seem, such a perception is at the root of our knowledge of things and individual accidents are merely grafted on to this impersonal or “pure” perception.  Just because philosophers have overlooked it, and because they have failed to distinguish it from that which memory contributes to it, they have regarded Perception as a kind of interior and subjective vision, differing from Memory only by its greater intensity and not differing in nature.  In reality, however, Perception and Memory differ fundamentally.

Our conscious perception is just our power of choice, reflected from things as though by a mirror, so that representation arises from the omission of that in the totality of matter which has no bearing on our needs and consequently no interest for us.  “There is for images merely a difference of degree and not of kind between ‘being’ and ’being consciously perceived.’"[Footnote:  Matter and Memory, p. 30 (Fr. p. 25).] Consciousness—­in regard to external perception—­is explained by this indeterminateness and this choice.  “But there is in this necessary poverty of conscious perception, something that is positive, that foretells spirit; it is, in the etymological sense of the word, discernment.’"[Footnote:  Matter and Memory, p. 31 (Fr. p. 26).] The chief difficulty in dealing with the problems of Perception, is to explain “not how Perception arises, but how it is limited, since it should be the image of the whole and is in fact reduced to the image of that which interests you."[Footnote:  Matter and Memory, p. 34 (Fr. p. 29).] We only make an insuperable difficulty if we imagine Perception to be a kind of photographic view of things, taken from a fixed point by that special apparatus which is called an organ of perception—­a photograph which would then be developed in the brain-matter by some unknown chemical and psychical process.  “Everything happens as though your perception were a result of the internal motions of the brain and issued in some sort from the cortical centres.  It could not actually come from them since the brain is an image like others, enveloped in the mass of other images, and it would be absurd that the container should issue from the content.  But since the structure of the brain is like the detailed plan of the movements among which you have the choice, and since that part of the external images which appears to return upon itself, in order to constitute perception, includes precisely all the points of the universe which these movements could affect, conscious perception and cerebral movement are in strict correspondence.  The reciprocal dependence of these two terms is therefore simply due to the fact that both are functions of a third, which is the indetermination of the Will."[Footnote:  Matter and Memory, p. 35 (Fr. p. 29).]