[32] This is the truly inconceivable element in the physical theory. As I have shown in the pleading on the side of Atheism, the supposed inconceivability of cosmic harmony being due to mindless forces, is not of such a kind as wholly refuses to be surmounted by symbolic conceptions of a sufficiently abstract character. But it is impossible, by the aid of any symbols, to gain a conception of an eternal existence. And I may here point out, that if Mind is said to be the cause of evolution, not only does the statement involve the inconceivable proposition that such a Mind must be infinite in respect to its powers of supervision, direction, &c.; but the statement also involves a necessary alternative between two additional inconceivable propositions--viz., either that such a Mind must have been eternal, or that it must have come into existence without a cause. In this respect, therefore, it would seem that the theory of Atheism has the advantage over that of Theism; for while the former theory is under the necessity of embodying only a single inconceivable term, the latter theory is under the necessity of embodying two such terms. [33] Mr. Herbert Spencer has treated of this subject in his memorable controversy with Mill on the "Universal Postulate" (see _Psychology_, Sec. 427), and refuses to entertain the term "Inconceivable" as applicable to any propositions other than those wherein "the terms cannot, by any effort, be brought before consciousness in that relation which the proposition asserts between them." That is to say, he limits the term "Inconceivable" to that which is _absolutely_ inconceivable; and he then proceeds to affirm that all propositions "which admit of being framed in thought, but which are so much at variance with experience, in which its terms have habitually been otherwise united, that its terms cannot be put in the alleged relation without effort," ought properly to be termed "_incredible_" propositions. Now I cannot see that the class "Incredible propositions" is, as this definition asserts, identical with the class which I have termed "Relatively inconceivable" propositions. For example, it is a familiar observation that, on looking at the setting sun, we experience an almost, if not quite, insuperable difficulty in _conceiving_ the sun's apparent motion as due to our own actual motion, and yet we experience no difficulty in _believing_ it. Conversely, I entertain but little difficulty in _conceiving_--_i.e._, imagining--a shark with a mammalian heart, and yet it would require extremely strong evidence to make me _believe_ that such an animal exists. The truth appears to be that our language is deficient in terms whereby to distinguish between that which is wholly inconceivable from that which is with difficulty conceivable. This, it seems to me, was the principle reason of the dispute between Spencer and Mill above alluded to,--the former writer having always used the word "Inconceivable" in the