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which are called problems of maxima and minima. It has been resolved by some mathematicians, particularly by the ingenious Mr. Maclaurin, by a fluxionary calculation, which is to be found in the Transactions of the Royal Society of London. He has determined precisely the angle required; and he found, by the most exact mensuration the subject could admit, that it is the very angle in which the three planes in the bottom of the cell of a honeycomb do actually meet.

"Shall we ask here, who taught the bee the properties of solids, and to resolve problems of maxima and minima? We need not say that bees know none of these things. They work most geometrically, without any knowledge of geometry; somewhat like a child, who, by turning the handle of an organ, makes good music without any knowledge of music. The art is not in the child, but in him who made the organ. In like manner, when a bee makes its comb so geometrically, the geometry is not in the bee, but in that great Geometrician who made the bee, and made all things in number, weight, and measure.”

◊ 102. Instincts susceptible of slight modifications.

We usually speak of the instincts of animals as fixed and inflexible; and they undoubtedly are so in a considerable degree. Of this inflexibility, or fixed and particular direction which is appropriate to them, a multitude of facts might be brought as proof. Mr. Stewart, speaking of a blind old beaver, that had been taken and kept for a number of years in a pond by itself, asserts that the animal showed no inconsiderable degree of sagacity and mechanical contrivance in accomplishing particular ends; but these ends were in no respect subservient to its accommodation or comfort in its actual situation, although manifestly parts of those systematic instincts which belong to it in its social state. The animal seemed, he further observes, like a solitary wheel of a machine, which exhibits in its teeth marks of a reference to other wheels with which it was intended to co-operate.

It must be admitted, however, whatever may be the correctness of this general view, that instincts are not always found in a pure and unmixed state, but are suscep

tible of being modified from observation and experience. The consequence is, that the naturally invariable tendency of the instinct is frequently checked and controlled; and it acquires, in that way, an appearance of flexibility which does not belong to it in its pure state. Hence there is often seen in old animals a cunning and sagacity which is not discoverable in those that are young; a difference which could not exist if both old and young were governed in all cases by an unmixed instinct.-It is necessary that this remark should be kept in view in considering the subject of instincts, if we are desirous of possessing a proper understanding of it.

103. Instances of instincts in the human mind.

But it is not our design to enter particularly into the subject of the instincts of animals in this place, although this topic is undoubtedly one of exceeding interest both to the philosopher and the Christian. Such inquiries are too diverse and remote from our main object, which has particular, if not exclusive reference to the economy of human nature. There are certain instinctive tendencies in man as well as in the inferior animals; but they are few in number, and, compared with the other parts of his nature, are of subordinate importance. Some of them will now be referred to.

(I.) The action of respiration is thought, by writers who have given particular attention to the subject, to imply the existence of an instinct. We cannot suppose that the infant at its birth has learned the importance of this act by reasoning upon it; and he is as ignorant of the internal machinery which is put in operation, as he is of its important uses. And yet he puts the whole machinery into action at the very moment of coming into existence, and with such regularity and success that we cannot well account for it except on the ground of an instinctive impulse.

(II.) "By the same kind of principle," says Dr Reid (Essays on the Active Powers, iii., chap. ii.), "a new-born child, when the stomach is emptied, and nature has brought milk into the mother's breast, sucks and swallows its food as perfectly as if it knew the principles of

that operation, and had got the habit of working according to them.

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Sucking and swallowing are very complex operations. Anatomists describe about thirty pairs of muscles that must be employed in every draught. Of those muscles, every one must be served by its proper nerve, and can make no exertion but by some influence communicated by the nerve. The exertion of all those muscles and nerves is not simultaneous. They must succeed each other in a certain order, and their order is no less necessary than the exertion itself.-This regular train of operations is carried on according to the nicest rules of art by the infant, who has neither art, nor science, nor experience, nor habit.

"That the infant feels the uneasy sensation of hunger, I admit; and that it sucks no longer than till this sensation be removed. But who informed it that this uneasy sensation might be removed, or by what means? That it knows nothing of this is evident, for it will as readily suck a finger or a bit of stick as the nipple."

(III.) The efforts which men make for self-preservation, appear to be in part of an instinctive kind. If a man is in danger of falling from unexpectedly losing his balance, we say with much propriety that the instantaneous effort he makes to recover his position is instinctive. If a person is unexpectedly and suddenly plunged into a river, the first convulsive struggle which he makes for his safety seems to be of the same kind. His reasoning powers may soon come to his aid, and direct his further measures for his preservation; but his first efforts are evidently made on another principle. When a violent blow is aimed at one, he instinctively shrinks back, although he knew beforehand it would be aimed in sport, and although his reason told him there was no danger. We always instinctively close the eyelids when anything suddenly approaches them. Dr. Reid asserts that he bas seen this tried upon a wager, which a man was to gain if he could keep his eyes open while another aimed a stroke at them in jest. When we are placed on the summit of a high tower or on the edge of a precipice, although we are perfectly assured of our safety by the rea

soning power, the instinct of self-preservation is constantly suggesting other precautions.

104. Further instances of instincts in men.

(IV.) There is also a species of resentment which may properly be called instinctive. Deliberate resentment implies the exercise of reason, and is excited only by intentional injury. Instinctive resentment, on the other hand, operates, whether the injury be intentional or not, and precisely as it does in the lower animals.

Whenever we suddenly experience pain, which is caused by some external object, this feeling arises in the mind with a greater or less degree of power, and prompts us to retaliate on the cause of it.-A child, for instance, stumbles over a stone or stick of wood, and hurts himself, and, under the impulse of instinctive resentment, violently beats the unconscious cause of its suffering. Savages, when they have been struck by an arrow in battle, have been known to tear it from the wound, break, and bite it with their teeth, and dash it on the ground, as if the original design and impetus of destruction were in the arrow itself. All persons, of strong passions in particular, show the existence and workings of this instinct when they wreak their vengeance, as they often do, on inanimate objects, by beating or dashing them to pieces.

(V.) There is undoubtedly danger of carrying the doctrine of the instinctive tendencies of the human mind too far, but we may consider ourselves safe in adding to those which have been mentioned the power of interpreting natural signs. Whenever we see the outward signs of rage, pity, grief, joy, or hatred, we are able immediately to interpret them. It is abundantly evident that children, at a very early period, read and decipher, in the looks and gestures of their parents, the emotions and passions, whether of a good or evil kind, with which they are agitated.

It must be admitted, that the power of interpreting natural signs depends in part on experience and on deductions drawn from that experience; but the power is evidently in some degree instinctive. Often, when we see, both in children and in older persons, the strong out

ward manifestations of grief, when we are at the same time assured that there is but little of suffering in fact, we find ourselves very sensibly affected. So, when we see an actor on the stage with distorted countenance and accents of deep grief, the outward signs carry a momentary conviction and a momentary pang to our own hearts, in spite of the admonitions of reason; a circumstance which cannot well be accounted for, except on the ground that these signs speak to us with a natural power; that is to say, are instinctively interpreted.

105. Of the final cause or use of instincts.

Although the instincts, as a general statement, commend themselves less decisively to our regard and admiration than some other portions of the mind, they still have their important uses. It seems, in particular, to be the design of the instinctive part of our nature to aid and protect us in those cases where reason cannot come seasonably to our aid. According as the reasoning powers acquire strength, and prepare themselves more and more for the various emergencies to which we are exposed, the necessity of instinctive aids is proportionally diminished. But there are some cases which the reasoning power never can reach; and, consequently, our whole protection is in instinct.

It is evident, therefore, that they are a necessary part of our constitution; that they help to complete the mental system; and although of subordinate power and value in man, compared with the inferior animals, they still have their worth. As the reasoning power predominates in man, so instincts predominate in the lower animals; and as we do not expect to find the glory of reasoning in brutes, so we should not expect to discover the full excellence of instinctive powers in men; but should rather look for them in the insect and the worm, in the beasts of the field, and the fishes of the sea, and the fowls of the air, dwelling in them as a part of their nature, and blessing while they control and guide them.

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