Animals, then, have both instincts and intelligence; and so has man. A large part of human life proceeds from tendencies as purely, if not as vigorously, instinctive as those of animals. Man has social instincts, which create human society. Children play from an instinct. The maternal instinct in a human mother is, till modified by reflection, as spontaneous, universal, and necessary as the same instinct in animals. But in man the instincts are reduced to a minimum, and are soon modified by observation, experience, and reflection. In animals they are at their maximum, and are modified in a much less degree. It is sometimes said that animals do not reason, but man does. But animals are quite capable of at least two modes of reasoning, that of comparison and that of inference. They compare two modes of action, or two substances, and judge the one to be preferable to the other, and accordingly select it. Sir Emerson Tennent tells us that elephants, employed to build stone walls in Ceylon, will lay each stone in its place, then stand off and look to see if it is plumb, and, if not, will move it with their trunk, till it lies perfectly straight. This is a pure act of reflective judgment. He narrates an adventure which befell himself in Ceylon while riding on a narrow road through the forest. He heard a rumbling sound approaching, and directly there came to meet him an elephant, bearing on his tusks a large log of wood, which he had been directed to carry to the place where it was needed. Sir Emerson Tennent's horse, unused to these monsters, was alarmed, and refused to go forward. The sagacious elephant, perceiving this, evidently decided that he must himself go out of the way. But to do this, he was obliged first to take the log from his tusks with his trunk, and lay it on the ground, which he did, and then backed out of the road between the trees till only his head was visible. But the horse was still too timid to go by, whereupon the judicious pachyderm pushed himself farther back, till all of his body, except the end of his trunk, had disappeared. Then Sir Emerson succeeded in getting his horse by, but stopped to witness the result. The elephant came out, took the log up again, laid it across his tusks, and went on his way. This story, told by an unimpeachable witness, shows several successive acts of reasoning. The log-bearer inferred from the horse's terror that it would not pass; he again inferred that in that case he must himself get out of the way; that, to do this, he must lay down his log; that he must go farther back; and accompanying this was his sense of duty, making him faithful to his task; and, most of all, his consideration of what was due to this human traveler, which kept him from driving the horse and man before him as he went on.