III. The “external influences” referred to in the so-called “law,” mean chiefly attraction. Since no body could have momentum except through weight, another name for attraction, it follows that all free motion has reference to another body, and hence is curvilinear; thus we are rid of that embarrassing “straight line motion” which gives so much trouble in mechanics. It has all to be reduced back again through various processes to curvilinear movement. We come, finally, to consider the central point of this system: THE CORRELATION OF FORCES. Speaking of persistence of force, Mr. Spencer concedes (p. 252) that this doctrine is not demonstrable from experience. He says (p. 254): “Clearly the persistence of force is an ultimate truth of which no inductive proof is possible.” (P. 255): “By the persistence of force we really mean the persistence of some power which transcends our knowledge and conception.” (P. 257): “The indestructibility of matter and the continuity of motion we saw to be really corollaries from the impossibility of establishing in thought a relation between something and nothing.” (Thus what was established as a mental impotence is now made to have objective validity.) “Our inability to conceive matter and motion destroyed is our inability to suppress consciousness itself.” (P. 258): “Whoever alleges that the inability to conceive a beginning or end of the universe is a _negative_ result of our mental structure, cannot deny that our consciousness of the universe as persistent is a positive result of our mental structure. And this persistence of the universe is the persistence of that unknown cause, power, or force, which is manifested to us through all phenomena.” This “positive result of our mental structure” is said to rest on our “inability to conceive the limitation of consciousness” which is “simply the obverse of our inability to put an end to the thinking subject while still continuing to think.” (P. 257): “To think of something becoming nothing, would involve that this substance of consciousness having just existed under a given form, should next assume no form, or should cease to be consciousness.” It will be observed here that he is endeavoring to solve the First Antinomy of Kant, and that his argument in this place differs from Kant’s proof of the “Antithesis” in this, that while Kant proves that “The world [or universe] has no beginning,” etc., by the impossibility of the origination of anything in a “void time,” that Mr. Spencer proves the same thing by asserting it to be a “positive result of our mental structure,” and then proceeds to show that this is a sort of “inability” which has a subjective explanation; it is, according to him, merely the “substance of consciousness” objectified and regarded as the law of reality.