The foregoing is applied by Mr. Spencer in his argument relative to the origin of the Universe respecting which, he asserts that "three verbally intelligible suppositions may be made": (1) that it is self-existent, (2) that it was self-created, (3) that it was created by an external agency. "Which of these suppositions is most credible it is not needful here to enquire. The deeper question, into which this finally merges, is, whether any one of these is even conceivable in the true sense of the word." He shows that, since the mind refuses to accept the transformation of absolute vacuity into the existent, the theory of self-creation forces us back to a potential Universe whose self-creation was transition to an actual Universe, and that then, we must explain the existence of the potential Universe and that, similarly, creation by an external agency demands that we account for the genesis of the Creator, so that both of these theories involve the self-existence of a something. Therefore, I shall analyze his presentation of the first theory only. "Self-existence necessarily means existence without a beginning; and to form a conception of self-existence is to form a conception of existence without a beginning. Now by no mental effort can we do this. To conceive existence through infinite past-time, implies the conception of infinite past-time, which is an impossibility. To this let us add, that even were self-existence conceivable, it would not in any sense be an explanation of the Universe.... It is not a question of probability, or credibility, but of conceivability."