. . .l sense, can be trusted not suddenly to go out of existence and leave no trace behind. In other words, there seems some reason to suppose that anything which actually exists must be in some way or other perpetual; that real existence is not a capricious and changing attribute: arbitrary collocations and accidental relations may and must be temporary, but there may be in each a fundamental substratum which, if it can be reached, will be found to be eternal. I develop this idea further in the sequel. This is, at any rate, what Professor Haeckel was evidently groping after, as many others have groped before him, and the nature of this fundamental persistent entity or entities (for we must not assume without proof that there is only one: there may be several, and at any rate their ultimate unification may be a still further advanced and more transcendental problem) may with some appropriateness be called 'the problem of the universe,' since it is clearly the problem of existence. Pro. . . Read More