To this question certain persons are at once ready to give an answer. There was a time, they argue, when it seemed possible for one man to embrace the whole field of human knowledge. But human knowledge grew; the special sciences were born; each concerned itself with a definite class of facts and developed its own methods. It became possible and necessary for a man to be, not a scientist at large, but a chemist, a physicist, a biologist, an economist. But in certain portions of the great field men have met with peculiar difficulties; here it cannot be said that we have sciences, but rather that we have attempts at science. The philosopher is the man to whom is committed what is left when we have taken away what has been definitely established or is undergoing investigation according to approved scientific methods. He is Lord of the Uncleared Ground, and may wander through it in his compassless, irresponsible way, never feeling that he is lost, for he has never had any definite bearings to lose. Those who argue in this way support their case by pointing to the lack of a general consensus of opinion which obtains in many parts of the field which the philosopher regards as his own; and also by pointing out that, even within this field, there is a growing tendency on the part of certain sciences to separate themselves from philosophy and become independent. Thus the psychologist and the logician are sometimes very anxious to have it understood that they belong among the scientists and not among the philosophers. Now, this answer to the question that we have raised undoubtedly contains some truth. As we have seen from the sketch contained in the preceding pages, the word philosophy was once a synonym for the whole sum of the sciences or what stood for such; gradually the several sciences have become independent and the field of the philosopher has been circumscribed. We must admit, moreover, that there is to be found in a number of the special sciences a body of accepted facts which is without its analogue in philosophy. In much of his work the philosopher certainly seems to be walking upon more uncertain ground than his neighbors; and if he is unaware of that fact, it must be either because he has not a very nice sense of what constitutes scientific evidence, or because he is carried away by his enthusiasm for some particular form of doctrine. Nevertheless, it is just to maintain that the answer we are discussing is not a satisfactory one. For one thing, we find in it no indication of the reason why the particular group of disciplines with which the philosopher occupies himself has been left to him, when so many sciences have announced their independence. Why have not these, also, separated off and set up for themselves? Is it more difficult to work in these fields than in others? and, if so, what reason can be assigned for the fact?