The size of the human brain, relatively greater than that of almost any other animal; man's structure, adapting him to stand erect; his ability to exist in all climates; his power of subsisting on varied food: all these facts of his physical nature are associated with his superior mental power, but do not produce it. The question recurs, What enables him to stand at the head of the animal creation?
Perhaps the chief apparent distinctions between man and other animals are these:—
1. The lowest races of men use tools; other animals do not.
2. The lowest human beings possess a verbal language; other animals have none.
3. Man has the capacity of self-culture, as an individual; other animals have not.
4. Human beings, associated in society, are capable of progress in civilization, by means of science, art, literature, and religion; other animals are not.
5. Men have a capacity for religion; no animal, except man, has this.
The lowest races of men use tools, but no other animal does this. This is so universally admitted by science that the presence of the rudest tools of stone is considered a sufficient trace of the presence of man. If stone hatchets or hammers or arrowheads are found in any stratum, though no human bones are detected, anthropologists regard this as a sufficient proof of the existence of human beings in the period indicated by such a geologic formation. The only tools used by animals in procuring food, in war, or in building their homes, are their natural organs: their beaks, teeth, claws, etc. It may be added that man alone wears clothes; other animals being sufficiently clothed by nature. No animals make a fire, though they often suffer from cold; but there is no race of men unacquainted with the use of fire.[20]
No animals possess a verbal language. Animals can remember some of the words used by men, and associate with them their meaning. But this is not the use of language. It is merely the memory of two associated facts,—as when the animal recollects where he found food, and goes to the same place to look for it again. Animals have different cries, indicating different wants. They use one cry to call their mate, another to terrify their prey. But this is not the use of verbal language. Human language implies not merely an acquaintance with the meaning of particular words, but the power of putting them together in a sentence. Animals have no such language as this; for, if they had, it would have been learned by men. Man has the power of learning any verbal language. Adelung and Vater reckon over three thousand languages spoken by men, and any man can learn any of them. The negroes speak their own languages in their own countries; they speak Arabic in North Africa; they learn to speak English, French, and Spanish in America, and Oriental languages when they go to the East. If any animals had a verbal language, with its vocabulary and grammar, men would long ago have learned it, and would have been able to converse with them.
Again, no animal except man is capable of self-culture, as an individual. Animals are trained by external influences; they do not teach themselves. An old wolf is much more cunning than a young one, but he has been made so by the force of circumstances. You can teach your dog tricks, but no dog has ever taught himself any. Yet the lowest savages teach themselves to make tools, to ornament their paddles and clubs, and acquire certain arts by diligent effort. Birds will sometimes practice the tunes which they hear played, till they have learned them. They will also sometimes imitate each other's songs. That is, they possess the power of vocal imitation. But to imitate the sounds we hear is not self-culture. It is not developing a new power, but it is exercising in a new way a natural gift. Yet we must admit that in this habit of birds there is the rudiment, at least, of self-education.