motor processes in the brain and are afterwards projected into P. There
is not, however, an unextended image which forms itself in consciousness
and then projects itself into the position P. Really, the point P, and
the rays which it emits, together with the retina and nervous elements
affected in the process of perception, all form a single whole. The
point P is an indispensable factor in this whole and it is really in P
and not anywhere else that the image of P is formed and
perceived.[Footnote: Cf. Matter and Memory, p. 37 (Fr p. 31), also paper
entitled Notre croyance a la loi de causalite in the Revue de
metaphysique et de morale, 1900, p. 658.]

In the field of "pure" perception, that is to say, perception
unadulterated by the addition of memory-images, there can arise no image
without an object. "Sensation is essentially due to what is actually
present."[Footnote: Le Souvenir du present et la fausse reconnaissance,
p. 579 of Revue philosophique, Dec., 1908; also L'Energie spirituelle,
p. 141 (Mind-Energy).] Exactly how external stimuli, such as rays of a
certain speed and length, come to give us a certain image, e.g., the
sensation "red" or the sound of "middle C," we shall never understand.
"No trace of the movements themselves can be actually perceived in the
sensation which translates them."[Footnote: Time and Free Will, pp. 34-
35 (Fr. p. 26).] We only make trouble by regarding sensations in an
isolated manner and attempting to construct Perception from them. "Our
sensations are to our perceptions, that which the real action of our
body is to its possible or virtual action."[Footnote: Matter and Memory,
p. 58 (Fr. p. 48).] Thus, everything happens as if the external images
were reflected by our body into surrounding space. This is why the
surface of the body, which forms the common limit of the external and
internal, is the only portion of space which is both perceived and felt.
Just as external objects are perceived by me where they are, in