Omitting for later consideration the sameness of the self or ego, I have already discussed the uses of the word same within the field of the immediately known. It remains to consider the sameness of what is believed to lie beyond this, and to belong to a different kind of a world. When men discuss these supposed realities, in what senses of the word same may they reasonably think of them as the same? When a common, unreflective man, whose mind has not been, in the words of Bishop Berkeley, "debauched by learning," looks at a tree and thinks about it, he believes he sees a real tree, at a certain real distance from his body, and of a given real height and figure. It does not occur to him to make any distinction between the tree immediately perceived, and an inferred second tree, not immediately perceived, but represented by the former. There is the tree; he sees it; he can touch it; it seems to him but one: and he always talks as if there were but one tree to be discussed in the premises. That one tree, he thinks, is really extended; is really out in space beyond his body; is, in short, what it appears to be. To his unreflective mind this tree does not seem to be a representative or to be seen through a representative, but to be seen immediately and just where it really is. But when a man has begun to battle with the difficulties of reflection, and has learned to make a distinction between things and his ideas of the things, he will probably fall into unforeseen perplexities about this tree. He reflects that, when he closes his eyes, the tree disappears; that when he approaches it it looks green, and when he recedes from it it grows blue; that a man with a peculiar defect in his vision does not see it colored as he does; that when he makes a pressure on the side of one eyeball he sees two trees where before he saw only one; that when he makes such a pressure upon both eyeballs and moves them about a little he sees two trees moving about, although he knows real trees can not ordinarily be made to move about so easily. Such reflections lead him to distinguish between the tree as he sees it, and the tree as it really is, and he defines the tree as he sees it as the tree immediately known, and the real tree as the tree mediately known, a cause of the existence of the former. He now thinks that he sees directly only copies or representatives of real things, and as he believes these copies or representatives to be in his mind, and usually talks as if his mind were in his head, or at least in his body, he concludes that things immediately known must in many instances be much smaller than they seem, or perhaps lack extension altogether. How can a tree thirty feet high be in a man's mind? It is true, that, when I press upon my eyeballs in the manner described, I seem to see two trees of that size moving; but must it not be a mistake? Must we not assume that what is immediately seen only _seems_ extended, and stands for an