Note 22 — Chapter III

In order to remain brief, I have not thought fit to allude in the text to a question of metaphysics which closely depends on the one broached by me: the existence of an outer world. Philosophers who define sensation as a modality of our Ego are much embarrassed later in demonstrating the existence of an outer world. Having first admitted that our perception of it is illusory, since, when we think we perceive this world, we have simply the feeling of the modalities of our Ego, they find themselves powerless to demonstrate that this illusion corresponds to a truth, and invoke in despair, for the purpose of their demonstration, instinct, hallucination, or some a priori law of the mind. The position we have taken in the discussion is far more simple. Since every sensation is a fragment of matter perceived by a mind, the aggregate of sensations constitutes the aggregate of matter. There is in this no deceptive appearance, and consequently no need to prove a reality distinct from appearances. As to the argument drawn from dreams and hallucinations which might be brought against this, I have shown how it is set aside by a distinction between perceptibility and truth. It is no longer a matter of perception, but of reasoning. In other words, all that we see, even in dreams, is real, but is not in its due place.