Consider the attitude of self-consciousness. That man is self-conscious is a basic and perhaps a tragic fact that surely requires no proof. The power of thinking "I am I" is an ultimate endowment of personality, outside of which, except by an act of primordial faith, we cannot pass. The phenomenon of human growth from infancy to maturity proves that it is possible for this self-consciousness--this power of saying "I am I"--to become clearer and more articulate from day to day. It seems as impossible to fix upon a definite moment in a child's life where we can draw a line and say "_there_ he was unconscious of himself and _here_ he is conscious of himself" as it is impossible to observe as an actual visible movement the child's growth in stature. Between consciousness and self-consciousness the dividing line seems to be as difficult to define as it is difficult to define the line between sub-consciousness and consciousness. My existence as a self-conscious entity capable of thinking "I am I" is the basic assumption of all thought. And though it is possible for my thought to turn round upon itself and deny my own existence, such thought in the process of such a denial cuts the very ground away which is the leaping point of any further advance. Philosophy by such drastic scepticism is reduced to complete silence. You cannot build up anything except illusion from a basis that is itself illusion. If I were not self-conscious there would be no centre or substratum or coherence or unity in any thought I had. If I were not self-conscious I should be unable to think. Consider, then, the attribute of reason. That we possess reason is also a fact that carries with it its own evidence. It is reason which at this very moment--reason of some sort, at any rate--I am bound to use, in estimating the important place or the unimportant place which reason itself should occupy. You cannot derogate from the value of reason without using reason. You cannot put reason into an inferior category, when compared with will or instinct or emotion, without using reason itself to prove such an inferiority. We may come to the conclusion that the universe is rather irrational than rational. We may come to the conclusion that the secret of life transcends and over-brims all rationality. But this very conclusion as to the irrational nature of the mystery with which reason is attempting to deal is itself a conclusion of the reason. There is only one power which is able to put reason aside in its search for truth and that power is reason.