The laws of formal logic are coincident with the conclusions which can be drawn about regions of space, which overlap one another in the various possible ways. It is not difficult so to state the relations or to obtain a symmetrical poiograph. But to enter into this branch of geometry is beside our present purpose, which is to show the application of the poiograph in a finite and limited region, without any of those complexities which attend its use in regard to natural objects. If we take the latter—plants, for instance—and, without assuming fixed directions in space as representative of definite variations, arrange the representative points in such a manner as to correspond to the similarities of the objects, we obtain configuration of singular interest; and perhaps in this way, in the making of shapes of shapes, bodies with bodies omitted, some insight into the structure of the species and genera might be obtained. CHAPTER IX APPLICATION TO KANT’S THEORY OF EXPERIENCE When we observe the heavenly bodies we become aware that they all participate in one universal motion—a diurnal revolution round the polar axis. In the case of fixed stars this is most unqualifiedly true, but in the case of the sun, and the planets also, the single motion of revolution can be discerned, modified, and slightly altered by other and secondary motions. Hence the universal characteristic of the celestial bodies is that they move in a diurnal circle. But we know that this one great fact which is true of them all has in reality nothing to do with them. The diurnal revolution which they visibly perform is the result of the condition of the observer. It is because the observer is on a rotating earth that a universal statement can be made about all the celestial bodies. The universal statement which is valid about every one of the celestial bodies is that which does not concern them at all, and is but a statement of the condition of the observer. Now there are universal statements of other kinds which we can make. We can say that all objects of experience are in space and subject to the laws of geometry. Does this mean that space and all that it means is due to a condition of the observer? If a universal law in one case means nothing affecting the objects themselves, but only a condition of observation, is this true in every case? There is shown us in astronomy a _vera causa_ for the assertion of a universal. Is the same cause to be traced everywhere? Such is a first approximation to the doctrine of Kant’s critique. It is the apprehension of a relation into which, on the one side and the other, perfectly definite constituents enter—the human observer and the stars—and a transference of this relation to a region in which the constituents on either side are perfectly unknown.