A history of his evolution, based, like a political history, on episodes, cannot, of course, be written. But man is a bundle of parts and capabilities. By comparing the civilised being with the savage and the savage with lower animals, we are able to trace, in many important particulars at least, his natural history with a degree of certainty to which, I think, no political history can aspire. As our comprehension of adult man is helped by a knowledge of the development of the child, so our understanding of our species is aided by a study of its past. Armed with some clear conceptions of what man was, and is, we shall be the better fitted to investigate social and political change, and to perceive how it happens that while some nations have inherited the earth and the fruits thereof, others have stagnated or fallen into decay.
How Man Learns by Experience
At a certain stage in his development the caterpillar builds himself a cocoon. His dwelling is a wonderful structure, but from our human point of view the remarkable thing is that he does not learn to build it. He may never have seen a cocoon before, and he constructs only one in his life. Yet his work is perfect, or at least very excellent, and it is as good in its beginnings as in its endings. Evidently he owes nothing to experience, but is impelled and guided throughout by a faculty which we term instinct. An instinct may be defined as an innate, inherited impulse, an inclination to do a certain definite act, the instinctive act, on receipt of a certain definite stimulus or incitement to action. In the case of the caterpillar the stimulus appears to be the sight at the proper time of a suitable spot in which to build a cocoon. Since this particular impulse does not appear at the beginning of conscious life, it is termed a deferred instinct. Man, on the other hand, cannot build his house unless he first learns how to build. He depends, not on instinct, but on experience. The faculty by means of which experience is stored in the mind is memory. The faculty by means of which we use stored experience to guide present or future conduct is intelligence. When the contents of memory are very vast, and the processes of thought by which they are utilised comparatively difficult and complex, intelligence is termed reason. Intelligence and reason depend, therefore, on memory, on ability to learn, on capacity to profit by experience. Memory is not the whole of intelligence, but it is the basis of it. Without memory there could be feeling and emotion, but no thought, for the materials of thought would be lacking.
Instinct in Place of Memory
We always measure the intelligence of an animal by its power of profiting by experience. Thus, a cat is more intelligent than a rabbit because it can learn more; a dog, for the same reason, is still more intelligent. A purely instinctive animal, one that has no memory, can have no conception of its past, and therefore no idea of its future. It lives wholly in the immediate present; feeling, but not thinking. It acts entirely on inclination, not on reflection. It makes provision for the future, not with any notion of providing, but simply because it has an impulse to a certain course of action, the performance of which gives it pleasure of the kind a child derives from playing or eating, and with the ultimate result of which it is no more consciously concerned than a child. If a caterpillar sheltered in a hole with the idea, founded on past experience, of avoiding danger, his action would be intelligent. If, appealing to a memory in which a great number of complex experiences were stored, he took thought and designed himself a shelter in which provision was made for all sorts of remembered dangers, his action would be rational. But if, making no appeal to the past nor taking thought for the future, he builds only because impelled by an innate impulse, then, no matter how elaborate the edifice he rears, his action is instinctive.
Animals low in the scale of life—for example, most insects—appear incapable of learning. But often they are wonderfully equipped by instinct. The details of the behaviour of a small beetle, as quoted from Professor Lloyd Morgan, may not have been quite correctly ascertained, but they are sufficiently accurate for our purpose.
A certain beetle (Sitaris) lays its eggs at the entrance of the galleries excavated by a kind of bee (Anthophora), each gallery leading to a cell. The young larvæ are hatched as active little insects, with six legs, two long antennæ, and four eyes, very different from the larvæ of other beetles. They emerge from the egg in the autumn, and remain in a sluggish condition till the spring. At that time (in April) the drones of the bee emerge from the pupæ, and as they pass out through the gallery the Sitaris larvæ fasten upon them. There they remain till the nuptial flight of the Anthophora, when the larva passes from the male to the female bee. Then again they wait their chance. The moment the bee lays an egg, the Sitaris larva springs upon it. Even while the poor mother is carefully fastening up her cell, her mortal enemy is beginning to devour her offspring, for the egg of the Anthophora serves not only as a raft, but as a repast. The honey, which is enough for either, would be too little for both, and the Sitaris, therefore, at its first meal, relieves itself from its only rival. After eight days the egg is consumed, and on the empty shell the Sitaris undergoes its first transformation, and makes its appearance in a very different form.... It changes into a white, fleshy grub, so organised as to float on the surface of the honey, with the mouth beneath and the spiracles above the surface.... In this state it remains until the honey is consumed, and, after some further metamorphoses, develops into a perfect beetle in August.
Wonderful Instinct of the Beetle
The beetle has sense organs; therefore she feels. But we have no reason to suppose that she remembers or thinks. Memory would be of little use to her; therefore parsimonious Nature bestows little or none. Cast adrift in a hostile world, she must come into existence ready armed by instinct for the battle of life. She has no time to learn, and during the rapid and strange changes in her career has little opportunity of acquiring knowledge that could beneficially guide her future conduct. Since memory and its corollary reflection are most developed in the highest animals, and are imperceptible in the lower, they are clearly later and higher products of evolution than instinct.