If, as I hope to show, it is false; it will then follow, that if our own observation gives us any reason whatever, for believing in the existence of other persons, we must assume the existence, not only of our own perceptions, thoughts and feelings, but also of some, at least, among that other class of data, which I may now, for the sake of brevity, call sense contents we must assume that some of them exist, in precisely the same sense in which we assume that our perceptions, thoughts, and feelings exist.