There are four historical layers underlying the minds of civilized men—the animal mind, the child mind, the savage mind, and the traditional civilized mind. We are all animals and never can cease to be; we were all children at our most impressionable age and can never get over the effects of that; our human ancestors have lived in savagery during practically the whole existence of the race, say five hundred thousand or a million years, and the primitive human mind is ever with us; finally, we are all born into an elaborate civilization, the constant pressure of which we can by no means escape.
Each of these underlying minds has its special sciences and appropriate literatures. The new discipline of animal or comparative psychology deals with the first; genetic and analytical psychology with the second;[10] anthropology, ethnology, and comparative religion with the third; and the history of philosophy, science, theology, and literature with the fourth.
We may grow beyond these underlying minds and in the light of new knowledge we may criticize their findings and even persuade ourselves that we have successfully transcended them. But if we are fair with ourselves we shall find that their hold on us is really inexorable. We can only transcend them artificially and precariously and in certain highly favorable conditions. Depression, anger, fear, or ordinary irritation will speedily prove the insecurity of any structure that we manage to rear on our fourfold foundation. Such fundamental and vital preoccupations as religion, love, war, and the chase stir impulses that lie far back in human history and which effectually repudiate the cavilings of ratiocination.
In all our reveries and speculations, even the most exacting, sophisticated, and disillusioned, we have three unsympathetic companions sticking closer than a brother and looking on with jealous impatience—our wild apish progenitor, a playful or peevish baby, and a savage. We may at any moment find ourselves overtaken with a warm sense of camaraderie for any or all of these ancient pals of ours, and experience infinite relief in once more disporting ourselves with them as of yore. Some of us have in addition a Greek philosopher or man of letters in us; some a neoplatonic mystic, some a mediaeval monk, all of whom have learned to make terms with their older playfellows.
Before retracing the way in which the mind as we now find it in so-called intelligent people has been accumulated, we may take time to try to see what civilization is and why man alone can become civilized. For the mind has expanded pari passu with civilization, and without civilization there would, I venture to conjecture, have been no human mind in the commonly accepted sense of that term.
It is now generally conceded by all who have studied the varied evidence and have freed themselves from ancient prejudice that, if we traced back our human lineage far enough we should come to a point where our human ancestors had no civilization and lived a speechless, naked, houseless, fireless, and toolless life, similar to that of the existing primates with which we are zoologically closely connected.
This is one of the most fully substantiated of historical facts and one which we can never neglect in our attempts to explain man as he now is. We are all descended from the lower animals. We are furthermore still animals with not only an animal body, but with an animal mind. And this animal body and animal mind are the original foundations on which even the most subtle and refined intellectual life must perforce rest.
We are ready to classify certain of our most essential desires as brutish—hunger and thirst, the urgence of sleep, and especially sexual longing. We know of blind animal rage, of striking, biting, scratching, howling, and snarling, of irrational fears and ignominious flight. We share our senses with the higher animals, have eyes and ears, noses and tongues much like theirs; heart, lungs, and other viscera, and four limbs. They have brains which stand them in good stead, although their heads are not so good as ours. But when one speaks of the animal mind he should think of still other resemblances between the brute and man.
All animals learn—even the most humble among them may gain something from experience. All the higher animals exhibit curiosity under certain circumstances, and it is this impulse which underlies all human science.
Moreover, some of the higher animals, especially the apes and monkeys, are much given to fumbling and groping. They are restless, easily bored, and spontaneously experimental. They therefore make discoveries quite unconsciously, and form new and sometimes profitable habits of action. If, by mere fumbling, a monkey, cat, or dog happens on a way to secure food, this remunerative line of conduct will "occur" to the creature when he feels hungry. This is what Thorndike has named learning by "trial and error". It might better be called "fumbling and success", for it is the success that establishes the association. The innate curiosity which man shares with his uncivilized zoological relatives is the native impulse that leads to scientific and philosophical speculation, and the original fumbling of a restless ape has become the ordered experimental investigation of modern times. A creature which lacked curiosity and had no tendency to fumble could never have developed civilization and human intelligence.[l0]