We have first to determine the underlying structure of the classification, that is, we have to seek the chief Divisions, of which our plan shows seven; four theoretical and three practical ones. It will be a secondary task to subdivide them later into the 24 Departments and 128 Sections. We desire to divide the whole of knowledge in a fundamental way, and we must therefore start with the question of principle:--what is knowledge? This question belongs to epistemology, and thus falls, indeed, into the domain of philosophy. The positivist is easily inclined to substitute for the philosophical problem the empirical question: how did that which we call knowledge grow and develop itself in our individual mind, or in the mind of the nations? The question becomes, then, of course, one which must be answered by psychology, by sociology, and perhaps by biology. Such genetic inquiries are certainly very important, and the problem of how the processes of judging and conceiving and thinking are produced in the individual or social consciousness, and how they are to be explained through physical and psychical causes, deserves fullest attention. But its solution cannot even help us as regards the fundamental problem, what we mean by knowledge, and what the ultimate value of knowledge may be, and why we seek it. This deeper logical inquiry must be answered somehow before those genetic studies of the psychological and the sociological positivists can claim any truth at all, and thus any value, for their outcome. To explain our present knowledge genetically from its foregoing causes means merely to connect the present experience, which we know, with a past experience, which we remember, or with earlier phenomena which we construct on the basis of theories and hypotheses; but in any case with facts which we value as parts of our knowledge and which thus presuppose the acknowledgment of the value of knowledge. We cannot determine by linking one part of knowledge with another part of knowledge whether we have a right to speak of knowledge at all and to rely on it. We can thus not start from the childhood of man, or from the beginning of humanity, or from any other object of knowledge, but we must begin with the state which logically precedes all knowledge; that is, with our immediate experience of real life. Here, in the naïve experience in which we do not know ourselves as objects which we perceive, but where we feel ourselves in our subjective attitudes as agents of will, as personalities, here we find the original reality not yet shaped and remoulded by scientific conceptions and by the demands of knowledge. And from this basis of primary, naïve reality we must ask ourselves what we mean by seeking knowledge, and how this demand of ours is different from the other activities in which we work out the meaning and the ideals of our life.