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.