For if space was created, it must have been previously non-existent. The non-existence of space cannot, however, by any mental effort be imagined. It is one of the most familiar truths that the idea of space as surrounding us on all sides, is not for a moment to be got rid of—not only are we compelled to think of space as now everywhere present, but we are unable to conceive its absence either in the past or the future. And if the non-existence of space is absolutely inconceivable, then, necessarily, its creation is absolutely inconceivable. Lastly, even supposing that the genesis of the Universe could really be represented in thought as the result of an external agency, the mystery would be as great as ever; for there would still arise the question—how came there to be an external agency? To account for this only the same three hypotheses are possible—self-existence, self-creation, and creation by external agency. Of these the last is useless: it commits us to an infinite series of such agencies, and even then leaves us where we were. By the second we are practically involved in the same predicament; since, as already shown, self-creation implies an infinite series of potential existences. We are obliged therefore to fall back upon the first, which is the one commonly accepted and commonly supposed to be satisfactory. Those who cannot conceive a self-existent universe; and who therefore assume a creator as the source of the universe; take for granted that they can conceive a self-existent creator. The mystery which they recognize in this great fact surrounding them on every side, they transfer to an alleged source of this great fact; and then suppose that they have solved the mystery. But they delude themselves. As was proved at the outset of the argument, self-existence is rigorously inconceivable; and this holds true whatever be the nature of the object of which it is predicated. Whoever agrees that the atheistic hypothesis is untenable because it involves the impossible idea of self-existence, must perforce admit that the theistic hypothesis is untenable if it contains the same impossible idea.