VI. The Human Individuality

Most difficult to drive from the field will be the so-called physiological proofs for the subjectivity of our perceptions. If I exert pressure on my skin, I perceive it as a sensation of pressure. I can perceive the same pressure through the eye as light, and through the ear as sound. I perceive an electrical discharge through the eye as light, through the ear as sound, through the nerves of the skin as impact, through the nose as a phosphoric smell. What follows from this fact? Only this, that I perceive an electrical discharge (or a pressure) and then a certain quality of light, or a sound, perhaps a certain smell, and so on. If no eye were there, then the perception of a light quality would not accompany the perception of a mechanical concussion in the environment; without the presence of an organ of hearing, no perception of sound, and so on. By what right can one say that without organs of perception the whole process would not be present? Whoever concludes from the fact that an electrical process calls forth light in the eye that therefore what we experience as light is, outside of our organism, only a mechanical process of motion—he forgets that he is only passing from one perception to another, and not at all to something outside of perception. Just as one can say that the eye perceives a mechanical process of motion in its environment as light, one can just as well maintain that changing an object in an ordered way is perceived by us as a process of motion. If I paint a horse twelve times all the way around a rotatable disk, in exactly those forms which his body would assume if he were running along, then, through rotating the disk I can call forth an appearance of motion. I only need to look through an opening in such a way as to see, at the right intervals, the sequence of the horses' positions. I do not see twelve pictures of a horse, but rather the picture of a galloping horse.