"“[T]he word "eternal" must by him be taken to stand for what "temporal" does not and cannot stand for; namely, the unchangeable Ground presupposed by the changing temporal; the necessary as against the contingent; the independent as against the dependent; the primary as against the derivative; the self-existent as against that which exists in and through it; the genuine cause, the causa sui, as against that which is after all nothing but effect, however it may be tied, by the causa sui, in an unrupturable chain of antecedent and consequent. Or we may say it means the noumenon as against the phenomenon; or, in fine, the thing in itself as against the thing in other. That is, the relation between the eternal and the temporal is not, and cannot be, only another case of the temporal relation. The relation is just one of pure reason, and is, in fact, sui generis: the eternal does not precede the temporal by date, but only in logic; it is the sine qua non without which the temporal cannot exist, nor is even conceivable. In brief, throughout my book I mean by the "eternal" simply the Real as contrasted with the apparent; the world of self-active causes as contrasted with the world of derivative effects, in so far passive.”"