in the case of an officer, who lost at the same time the lively sense of his own identity and of the reality of the outer world, and had the feeling of being sunk in a dream." Again, "In all the cases collected by Krishaber, the patient suddenly fell a victim to dizziness, roaring in the ears, and disturbances of sight, hearing and touch. An especially accurate observer of himself says: 'These disturbances of sight reminded me of how things look when seen through powerful concave lenses, or when one stands beside a very hot furnace and looks through the draft, so that the objects beheld seem to tremble. My own disturbances of sight resemble a combination of these two.' The disturbances of hearing were even more pronounced. And every time there proceeds from these altered conditions, especially from the sense-disturbances, an alteration in the sense of the reality of the outer world, and a parallel change in self-consciousness."
The patient first observed was a writer. After violent sense-disturbances he seemed to be dreaming and no longer the same person. Both his own identity and the outer world became matters of uncertainty to him. Another case was that of an English officer. "It seemed to the patient that something was wrapped about him and stood as a barrier between him and the outer world, giving him a feeling of complete isolation. When he spoke, his voice seemed strange, he did not recognize it or believe it was his own. . . . He doubted his own existence. He seemed to be not himself, and it cost him an effort to believe in the identity of his own person. At times he was not sure of his existence, and at the same time he lost belief in the reality of the outer world, and was as if sunk deep in a dream." It seemed to a third patient as though persons about him were figures in a dream. He thought he was no longer the same person, and as he walked he was unable to feel the floor.
I cite these cases to support the opinion that the experience of an outer world is rooted in the very organization of our being. Just what these deep-lying roots are is a special problem for psychology, but the fact that such experience does express some essential factor in our organization justifies us in speaking of a natural view of the world as contrasted with the idealistic point of view. For although we may not be justified in comparing crude organic attitudes with any reasoned metaphysic, still these natural attitudes of adjustment give rise to the naïve realism of the 'plain man,' and this it is on which a reflected realism depends.
The proposal of the problem, how we come to know an outer world, as a problem for empirical psychology, does seem to contain the implication that such experience expresses the natural adjustment of the physiological subject.