Sensation

. . . .The sense organ appears to us to be affectged by the stimulant; the protoplasmic and physical-chemical modifications which appear in the sense organ are not actually produced by that organ; they come to it ‘from’ the outside. At least we assert this in order to remain faithful to the principle of inertia which constitutes all nature as exteriority. Therefore when we establish a correlation between the objective system (stimulant-sensory organ) which we presently perceive, and the subjective system which for us is the ensemble of the internal properties of the other object, then we are compelled to admit that the new motion with the stimulation of the sense is also produced by something other than itself. If it were produced spontaneously, in fact, it would immediately be cut off from all connection with the organ stimulated, or if you prefer, the relation which could be established between them would be ‘anything whatsoever.’ Therefore we shall conceive of an objective unity corresponding to even the tiniest and shortest of perceptible stimulations, and we shall call it sensation. . . . Page 413