Almost everyone would agree, therefore, that what we call "life" is a higher and more important achievement of nature. And if we wish to grade this life, we do so according to its sentience--that is to say, the amount and intensity of the consciousness which grows in it. We are interested in the one-celled organisms which swarm everywhere throughout nature, and we study the mysterious processes by which they nourish and beget themselves; we suspect that they have a germ of consciousness in them; but we are surer of the meaning and importance of the consciousness we detect in some complex organism like a fish or bird. We learn to know the signs of consciousness, of dawning intelligence, and we esteem the various kinds of creatures according to the amount of it they possess. We reject mere physical bigness and mere strength. Joyce Kilmer may write: "Poems are made by men like me, But only God can make a tree"-- And that seems to us a charming bit of fancy; but the common sense of the thing is voiced to us much better in the lines of old Ben Jonson: "It is not growing like a tree In bulk doth make man better be." If we take two animals of equal bulk, the hippopotamus and the elephant, we shall be far more interested in the elephant, because of the intelligence and what we call "character" which he displays. There are good elephants and bad elephants, kind ones and treacherous ones. We love the dog because we can make a companion of him; that is, because we can teach him to react to human stimuli. Of all animals we are fascinated most by the monkey, because he is nearest to man, and displays the keenest intelligence. Someone may say that this is all mere human egotism, and that we have no way of really being sure that the life of elephants and hippopotami is not more interesting and significant than the life of men. Never having been either of these animals, I cannot say with assurance; but I know that I have the power to exterminate these creatures, or to pen them in cages, and they are helpless to protect themselves, or even to understand what is happening to them. So I am irresistibly driven to conclude that intelligence is more safe and more worth while than unintelligence; in short, that intelligence is nature's highest product up to date, and that to foster and develop it is the best guess I can make as to the path of wisdom--that is, of intelligence!