CHAPTER III. THE “FIRST PRINCIPLES” OF THE “KNOWABLE.” As might be expected from Spencer’s treatment of the _unknowable_, the _knowable_ will prove a confused affair; especially since to the above-mentioned “inscrutability” of the absolute, he adds the doctrine of an “obscure consciousness of it,” holding, in fact, that the knowable is only a relative, and that it cannot be known without at the same time possessing a knowledge of the unknowable. (P. 82) he says: “A thought involves relation, difference and likeness; whatever does not present each of them does not admit of cognition. And hence we may say that the unconditioned as presenting none of these, is trebly unthinkable.” And yet he says, (p. 96): “The relative is itself inconceivable except as related to a real non-relative.” We will leave this infinite self-contradiction thus developed, and turn to the positions established concerning the knowable. They concern the nature of Force, Matter and Motion, and the predicates set up are “persistence,” “indestructibility” and similar. THE KNOWABLE. Although in the first part “conceivability” was shown to be utterly inadequate as a test of truth; that with it we could not even establish that the earth is round, or that space is infinitely continuous, yet here Mr. Spencer finds that inconceivability is the most convenient of all positive proofs. The first example to be noticed is his proof of the compressibility of matter (p. 51): “It is an established mechanical truth that if a body moving at a given velocity, strikes an equal body at rest in such wise that the two move on together, their joint velocity will be but half that of the striking body. Now it is a law of which the negative is inconceivable, that in passing from any one degree of magnitude to another all intermediate degrees must be passed through. Or in the case before us, a body moving at velocity 4, cannot, by collision, be reduced to velocity 2, without passing through all velocities between 4 and 2. But were matter truly solid—were its units absolutely incompressible and in unbroken contact—this ‘law of continuity, as it is called, would be broken in every case of collision. For when, of two such units, one moving at velocity 4 strikes another at rest, the striking unit must have its velocity 4 instantaneously reduced to velocity 2; must pass from velocity 4 to velocity 2 without any lapse of time, and without passing through intermediate velocities; must be moving with velocities 4 and 2 at the same instant, which is impossible.” On page 57 he acknowledges that any transition from one rate of motion to another is inconceivable; hence it does not help the matter to “pass through intermediate velocities.” It is just as great a contradiction and just as inconceivable that velocity 4 should become velocity 3.9999+, as it is that it should become velocity 2; for no change whatever of the