Coming from abstractions to the common, everyday details of our lives, we find that our whole life is a contradiction, a mixture of existence and non-existence. There is this contradiction in knowledge. It seems that man can know everything, if he only wants to know; but before he has gone a few steps, he finds an adamantine wall which he cannot pass. All his work is in a circle, and he cannot go beyond that circle. The problems which are nearest and dearest to him are impelling him on and calling, day and night, for a solution, but he cannot solve them, because he cannot go beyond his intellect. And yet that desire is implanted strongly in him. Still we know that the only good is to be obtained by controlling and checking it. With every breath, every impulse of our heart asks us to be selfish. At the same time, there is some power beyond us which says that it is unselfishness alone which is good. Every child is a born optimist; he dreams golden dreams. In youth he becomes still more optimistic. It is hard for a young man to believe that there is such a thing as death, such a thing as defeat or degradation. Old age comes, and life is a mass of ruins. Dreams have vanished into the air, and the man becomes a pessimist. Thus we go from one extreme to another, buffeted by nature, without knowing where we are going.