Experience teaches that the distinction between the ‘I’ and the ‘not-I’ is really only a question of a habit of thought, of a form of thought, and not of an effective, certain knowledge, which carries in itself the criteria of its accuracy and certitude. When, in consequence of a morbid disturbance, our sensory nerves or their centres of perception are excited, and consciousness acquires knowledge of this excitation, it imputes to it without hesitation, according to its habit, an external cause existing in the ‘not-I.’ Hence arise illusions and hallucinations, which the patient takes for realities, and that so positively that there is absolutely no means of convincing him that he perceives facts passing within him, not outside of him. In the same manner consciousness concludes that the movements executed unconsciously are occasioned by an extraneous will. It perceives the movement, but it has not noticed that the habitual internal cause, viz., a motor image and an act of the will, has preceded it; hence it places the cause of the movement without hesitation in the ‘not-I,’ although it resides in the ‘I,’ and is only occasioned by subordinate centres, the activity of which remains concealed from consciousness. This it is which gives rise to spiritualism, which, in so far as it is in good faith and not openly a hocus-pocus, is simply a mystical attempt to explain movements, the real cause of which consciousness does not find in itself, and which it places, in consequence, in the ‘not-I.’
In ultimate analysis, the consciousness of the ‘Ego,’ and notably the opposition of the ‘Ego’ and the ‘non-Ego,’ is an illusion of the senses and a fallacy of thought. Every organism is related to a species, and, over and above that, to the universe. It is the direct material continuation of its parents; it is itself continued directly and materially in its descendants. It is composed of the same materials as the whole environing world; these materials are constantly penetrating into it, transforming it, producing in it all the phenomena of life and consciousness. All the lines of action of the forces of nature are prolonged in its interior; it is the scene of the same physical and chemical processes in action throughout the universe. What pantheism divines and clothes in needlessly mystic words is clear, sober fact, namely, the unity of nature, in which each organism is also a part related to the whole. Certain parts are more nearly connected; others are more separated from one another. Consciousness perceives only the closely-knit parts of its physical basis, not those more remote. Thus it falls into the illusion that the parts near together alone belong to it, and that the more distant are strangers to it, and to consider itself as an ‘individuum,’ confronting the world as a separate world or microcosm. It does not observe that the ‘I,’ so rigidly posited, has no fixed limits, but continues and spreads beneath the threshold of consciousness, with an ever-diminishing distinctness of separation, to the extreme depths of nature, till it blends there with all the other constituents of the universe.