=17. The Classification of the Sciences.= From the preceding observations the means may be drawn for outlining a complete table of the sciences. However, we must not regard it complete in the sense that it gives every possible ramification and turn of each science, but that it sets up a frame inside of which at given points each science finds its place, so that, in the course of progressive enlargement, the frame need not be exceeded. The basic thought upon which this classification rests is that of graded abstraction. We have seen (p. 19) that a concept is all the more general, that is, is applicable to all the more experiences, the fewer parts or elementary concepts it contains. So we shall begin the system of the sciences with the most general concepts, that is, the elementary concepts (or with what for the time being we shall have to consider elementary concepts), and, in grading the concept complexes according to their increasing diversity, set up a corresponding graded series of sciences. One thing more is to be noted here, that this graded series, on account of the very large number of new concepts entering, must produce a correspondingly great number of diverse sciences. For practical reasons groups of such grades have been combined temporarily. Thereby a rougher classification, though one easier to obtain a survey of, has been made. The most suitable and lasting scheme of this sort was originated by the French philosopher, _Auguste Comte_, since whom it has undergone a few changes. Below is the table of the sciences, which I shall then proceed to explain: I. _Formal Sciences._ Main concept: order Logic, or the science of the Manifold Mathematics, or the science of Quantity Geometry, or the science of Space Phoronomy, or the science of Motion II. _Physical Sciences._ Main concept: energy Mechanics Physics Chemistry III. _Biological Sciences._ Main concept: life Physiology Psychology Sociology