Every man knows what it is to live, and his immediate experience will verify those features of the adventure that stand out conspicuously. To begin with, life is our birthright. We did not ask for it, but when we grew old enough to be self-conscious we found ourselves in possession of it. Nor is it a gift to be neglected, even if we had the will. As is true of no other gift of nature, we must use it, or cease to be. There is a unique urgency about life. But we have already implied more, in so far as we have said that it must be _used_, and have thereby referred to some form of movement or activity as its inseparable attribute. To live is to find one's self compelled to do something. To do _something_--there is another implication of life: some outer expression, some medium in which to register the degree and form of its activity. Such we recognize as the environment of life, the real objects among which it is placed; which it may change, or from which it may suffer change. Not only do we find our lives as unsolicited active powers, but find, as well, an arena prescribed for their exercise. That we shall act, and in a certain time and place, and with reference to certain other realities, this is the general condition of things that is encountered when each one of us discovers life. In short, to live means to be compelled to do something under certain circumstances. There is another very common aspect of life that would not at first glance seem worthy of mention. Not only does life, as we have just described it, mean opportunity, but it means self-conscious opportunity. The facts are such as we have found them to be, and as each one of us has previously found them for himself. But when we discover life for ourselves, we who make the discovery, and we who live, are identical. From that moment we both live, and know that we live. Moreover, such is the essential unity of our natures that our living must now express our knowing, and our knowing guide and illuminate our living. Consider the allegory of the centipede. From the beginning of time he had manipulated his countless legs with exquisite precision. Men had regarded him with wonder and amazement. But he was innocent of his own art, being a contrivance of nature, perfectly constructed to do her bidding. One day the centipede discovered life. He discovered himself as one who walks, and the newly awakened intelligence, first observing, then foreseeing, at length began to direct the process. And from that moment the centipede, because he could not remember the proper order of his going, lost all his former skill, and became the poor clumsy victim of his own self-consciousness. This same self-consciousness is the inconvenience and the great glory of human life. We must stumble along as best we can, guided by the feeble light of our own little intelligence. If nature starts us on our way, she soon hands over the torch, and bids us find the trail for ourselves.