In order to justify them, we must in the first place recall the conclusions arrived at in an earlier stage of this treatise. We saw reason to hold that the existence of one connected world, which is the presupposition of knowledge, implies the action of one self-conditioning and self-determining mind; and that, as our knowledge, so our moral activity was only explicable on supposition of a certain reproduction of itself, on the part of this eternal mind, as the self of man—a reproduction of itself to which it makes the processes of animal life organic, and which is qualified and limited by the nature of those processes, but which is so far essentially a reproduction of the one supreme subject, implied in the existence of the world, that the product carries with it under all its limitations and qualifications the characteristic of being an object to itself (§99). Proof of such a doctrine, in the ordinary sense of the word, from the nature of th e case there cannot be. It is not a truth deducible from other established or conceded truths. It is not a statement of an event or matter of fact that can be the object of experiment or observation. It represents a conception to which no perceivable or imaginable object can possibly correspond, but one that affords the only means by which, reflecting on our moral and intellectual experience conjointly, taking the world and ourselves into account, we can put the whole thing together and understand how (not why, but how) we are and do what we consciously are and do. Given this conception, and not without it, we can at any rate express that which it cannot be denied demands expression, the nature of man’s reason and man’s will, of human progress and human short-coming, of the effort after good and the failure to gain it, of virtue and vice, in their connection and in their distinction, in their essential opposition and no less essential unity. (§174 ¶1)