Images de page
PDF
ePub

mediate nature between matter and mind; or else are in some instances simply material, and in others simply mental.

The very excellent and learned Cudworth belonged to the first of these two divisions, and may be regarded as having taken the lead in the scheme which it developes. I have already observed, in a former study, that this profound metaphysician was so strongly attached to the Platonic theory of ihe creation of the world, that he strove, with the full force of his mighty mind, to restore this theory to general vogue. And as it was one important principle in this theory that incorporeal form, or an active and plastic nature, exists throughout the world independently of pure mind and pure matter, and that the last is solely rendered visible and endowed with manifest properties by a union with this active intermede, Cudworth conceived that all instinctive powers might be satisfactorily resolved into the operation of the same secondary energy in proportion as it pervades the universe.* In opposition to which doctrine, however, it is sufficient to remark, that as the existence of all visible matter, whether organized or unorganized, upon the leading principle of the Platonic theory, is equally the result of this plastic power, and produced by a union with it, it should follow that unorganized matter ought occasionally at least to give proofs of an instinctive faculty, as well as matter in an organized state ; proofs of definite means to accomplish a definite end, and that end the general weal, preservation, or reproduction of the body exhibiting it. But as, by the common consent of all mankind, no such faculty is ever to be traced in unorganized matter, it cannot be referred to a principle which is equally common and essential to all visible matter, whether under an organized or an unorganized modification.

At the head of the second division of the last class of philosophers to whom I have referred, we may perhaps place M. Buffon; who, incapable of acceding altogether to the mechanical hypothesis of Des Cartes, yet not choosing to allot to animals below the rank of man the possession of an intelligent principle, kindly endowed them with the property of life, which Des Cartes had morosely withheld by contending that they were mechanical machines alone, and very obligingly allowed them to possess a faculty of distinguishing between pleasure and pain, together with a general desire for the former and a general aversion for the latter. And having thus equipped the different tribes of brutes, he conceived that he had sufficiently accounted for the existence of instinctive actions, by leaving them to the operation of this distin. guishing faculty upon the mechanical properties of their respective organs. M. Reimar, however, an ingenious German professor, who flourished towards the close of the last century, did not conceive in the same manner: and hence, in a work immediately directed to the instinct of animals, and published at Hamburgh in 1769, he divides the actions which he apprehends ought to pass under this name into three classes-mechanical, representative, and spontaneous: by the first intending all the proper actions of animal organs over which the will has no control, as the pulsation of the heart, the secretion of the various fluids, and the dilatation of the pupil; by the second, those which depend upon an imperfect kind of memory, and which, so far as it is memory, brutes enjoy in common with mankind; and by the third, those which originate from M. Buffon's admitted faculty of distinguishing pleasure from pain, and the desire consequent upon it of possessing the one and avoiding the other.

It is, however, a sufficient answer to both these opinions, which in truth are founded upon one common basis, that, like the theories of Darwin and Smellie, they equally confound, though in a different manner, powers that are essentially distinct. The founders of these opinions may, with Darwin and Smellie, derive the instinctive faculty from a principle of mind, or with Des Cartes and Dr. Reid from a principle of body; but they have no right to derive it from both, or to contend that its different ramifications originate in some instances from the one source, and in others from the other: though, as

* Intellect. Syst. 1743

I have already observed, if they do derive it from mind alone, they will be compelled to admit its existence in a thousand cases in which not a single attribute of mind can be traced; while, if they derive it from body alone, they offer a cause that is inadequate to the effect produced.

M. Cuvier has taken a ground still different from any of these philosophers. He has not, indeed, expressly written upon the subject, but in a very accurate description of a somewhat singular ourang-outang,* he sufficiently unfolds his opinion, that instinct consists of ideas which do not originate from sensation, but flow immediately from the brain, and are truly innate. His words are as follows: "The understanding may have ideas without the aid of the senses; two-thirds of the brute creation are moved by ideas which they do not owe to their sensations, but which flow immediately from their brain. Instinct constitutes this order of phenomena: it is composed of ideas truly innate, in which the senses have never had the smallest share.” There is a perplexity in this passage, which I am surprised at in the writings of so exact a physiologist : it first confounds instincts with ideas, as other philosophers have confounded them with feelings; and next affirms that ideas may flow from the brain without the aid of the external senses. That “the understanding may have ideas without the aid of the senses," I admit; but then it can. not have them from the brain, this being the very foundation and fountain of the senses; that from which they rise, and that in which they terminate. The understanding may, undoubtedly, have ideas from the exercise of its own proper powers alone, bụt this can only be the case with pure intellectual beings, and to assimilate the faculty of instinct with a faculty of this exalted character, is to clothe brutes with endowments superior to those of mankind; it is to elevate the ourang-outang above an Aristotle or a Bacon.

Hence M. Dupont de Nemours, in an article read before the National Institute in 1807, advises to drop the term instinct altogether, as the only means of avoiding the rocks on some of which every writer has shipwrecked himself. He asserts, that there is in fact no such thing in existence; and that every action which has hitherto been described under such name is the mere result of intelligence, of thought, habit, example, or the association of ideas. But this is only to revive, in a new form, the theory of Darwin or of Smellie; while it is only necessary to advert to the explanatory examples offered by M. Dupont himself, to see that many of them are utterly incapable, by any ingenuity whatever, of being resolved into a principle either of intelligence or of mechanism.t

Nothing, therefore, is clearer than that the principle of instinct has hitherto never been explicitly pointed out, nor even the term itself precisely defined: it has been derived from mechanical powers, from mental powers, from both together, and from an imaginary intermediate essence, supposed equally to pervade all imbodied matter, and to give it form and structure. It has been made sometimes to include the sensations, sometimes the passions, sometimes the reason, and sometimes the ideas: it has sometimes been re stricted to animals, and sometimes extended to vegetable life. I

• Annales du Museum et d'Hist. Nat. tom. xvi. p. 46. | Magazine Encyclopedique, Feb. 1807, p. 437.

Dr. Hancock has lately published a very elaborate volume upon this subject, in which he takes a just view of the instinctive powers of animals, and is half-disposed to allow the same faculty to plants. But in merely distinguishing this faculty from reason, in the same way in which he distinguishes what have hitherto been called ionate principles, a moral sense or faculty, light of nature, divine reason, as contradistinguished from human reason, spiritual power, internal teaching, and even impulse and inspiration of the Holy Spirit, all which he contemplates as intelligences of a like kind, or, to adopt his own words, * which we can only regard as an EM ANATION of Divine Wisdom,” he has so completely generalized the subject, not to say apparently blended into a common principle powers which have usually been regarded as specifically discrepant from each other,---even allowing the existence of the whole of them, and that they all flow, as in such case they must necessarily do, from the same almighty Source of being, -that-the pecutiar nature of the instinctive faculty is left in as much obscurity as ever.

Dr. Hancock has tiodden over an extensive ground of both physical and metaphysical research, and the excellent spirit with which he writes entitles him to the esteem of every good man. Yet I am at a loss to determine why the principle of reason, or the reasoning soul in man, should not have as fair a claim to origioate from the divine energy that pervades every part of nature, from the minutest atom to the highest spiritual adlation, as the faculty of instinct. By throwing, however, the principle of human reason out of the general palo, and by associating insunct with the high alliances just adverted to, the “ unconscious intelligence," as Dr. Hancock has denominated it of the lowest part of the animal creation, even that of insecta

Under these circumstances I shall beg your candid attention to a new view of the subject, and a view that may tend to give us a more definite idea of the nature of the action, and consequently of the extent and real meaning of the term.

In an early lecture of the preceding series* I endeavoured to point out the cominon or essential, and many of the peculiar, properties of inorganic matter; and in a subsequent studyt I attempted to lay down the more prominent characters by which inorganic is distinguished from organic matter, as a stone, for example, from a plant or an animal. I observed that, on investigating the history of the stone, it would be found to have been produced fortuitously; to have grown by external accretion, and only to be destructible by chemical or mechanical means: while, on investigating the history of the plant or the animal, it would be found to have been produced by generation; to have grown by nutrition, or internal instead of external accretion; and to be destructible by death; to be actuated by an internal power, and possessed of parts mutually dependent, and contributing to each other's functions. I ob. served farther, that in what this internal power consists we know not; that in plants and animals it appears to be somewhat differently modified, but that wherever we meet with it we term it the PRINCIPLE OF LIFE, and characteri e the individual substance it actuates by the name of an organized being, from its possession of organized parts, in contradistinction to all those substances which are destitute as well of life as of internal organs, and which are hence denominated unorganized.

Upon another occasion I took a brief survey of the chief theories which have been offered upon the nature of this mysterious and sugitive essence :I which I observed was altogether a distinct principle from that of thoughi, and from that of sensation, for both these must also be kept distinguished from each other. I remarked, that in modern times it had at one period been said to be derived from caloric, thermogen, or the elementary matter of heat, as it exists in the organized system, from the well ascertained importance of this substance (if it be a substance) towards the perfection, and even continuance, of all the vital functions: that at another time it was, for the same reason, supposed to consist of oxygen introduced into the system by every act of inspiration; and still more lately of the Voltaic aura, in consequence of those wonderful effects which this aura is now well known to produce on the muscular fibres of animals, not only during life, but often for some hours after death has taken place. I remarked farther, that Mr. John Hunter had traced this living principle to many of the organized fluids, as well as to the solids; and that he had especially developed it in the blood, which, coincidently with the Mosaic declaration, he believed to be its immediate seat. “The difficulty," observes he," of conceiving that the blood is endowed with life while circulating, arises merely from its being a fluid; and the mind not being accustomed to the idea of a living fluid.”'And I observed, that by a variety of important and well-defined experiments, this enterprising and indefatigable indagator had succeeded in proving, not only that it contributes in a greater degree to the vital action and to the vital material of the general system than any other constituent part of it, whether solid or fluid, but has all the essential properties of life; that it is capable of being acted upon, and contracting, like the muscular fibre, upon the application of an appropriate stimulus, as atmospheric air, for example; on which occasion it becomes constringed into that cake or coagulum which every one must have beheld in blood drawn from the arm: that in all degrees of atmospherical temperature, of heat or cold, which the body is capable of enduring, it maintains an and worms, is raised to a loftier and diviner rank than the peculiar principle by which man has hitherto been supposed to exercise a dominion over the rest of creation. “In the lowest order of animals," says Dr. Hancock, "the divine energy seems to act with most unimpeded power. It is less and less concentrated in the successive links of the living chain upward to man.-The lowest animal has this divine power, not of free choice, nor consciously: the "LIEST of men has it also, but consciously and willingly: and it then be comes bis ruling principle; his divine counsellor; his never failing help; a light to his feet, and a lantern to bis path."-Essay on Instinct, and its Physical and Moral Relations, p. 170_313

| Series 1. Lecture viii. Series 1. Lecture x.

Essay on the Blood, &c. p. 20.

• Series 1. Lecture iv.

equality in its own temperature with scarcely any variation : that in the case of paralytic limbs it is the only power that continues vitality in them and preserves them from corruption : that though not vascular itself, it is capable by its own energy of producing new vessels out of its own substance, and vessels, too, of every description, lymphatics, arteries, and even nerves; and, finally, that though, like the muscular fibre, it is capable of contracting upon the application of a certain degree of appropriate stimulus, like the muscular fibre, also, it is instantly exhausted of its vital power whenever such stimulus is excessive ; and that the stroke of lightning which destroys the muscular fibre and leaves it flaccid and incontractile, destroys likewise the blood, and leaves it loose and incoagulable.

In every organized system, then, whether animal or vegetable, and in every part of such system, whether solid or fluid, we trace an evident proof of that controlling and identifying power which physiologists have denominated, and with much propriety, the PRINCIPLE OF LIFE. Of its cause and nature we know no more than we do of the cause and nature of gravitation or magnetism. It is neither essential mind nor essential matter; it is neither passion nor sensation; but, though unquestionably distinct from all these, is capable of combining with any of them : it is possessed of its own book of laws, to which, under the saine circumstances, it adheres without the smallest deviation; and its sole and uniform aim, whether acting generally or locally, is that of health, preservation, or reproduction. The agency by which it operates is that which we denominate or should denominate INSTINCT, and the actions by which its sole and uniform aim is accomplished are what we mean or should mean by INSTINCTIVE ACTIONS; or, to speak somewhat more precisely, instinct is the operation of the living principle, whenever manifestly directing its operations to the health, preservation, or reproduction of a living frame, or any part of such frame.*

The law of instinct, then, is the law of the living principle: instinctive actions are the actions of the living principle; and either is that power which characteristically distinguishes organized from unorganized matter, and pervades and regulates the former as gravitation pervades and regulates the lat. ter, uniformly operating by definite means, in definite circumstances, to the general welfare of the individual system or of its separate organs; advancing them to perfection, preserving them in it, or laying a foundation for their reproduction, as the nature of the case may require. It applies equally to plants and to animals, and to every part of the plant as well as to every part of the animal, so long as such part continues alive.f It is this which maintains from age to age, with so much nicety and precision, the distinctive characters of different kinds and species; which, as is noticed in a preceding study, carries off the waste or worn out matter, supplies it with new,f and in a thousand instances suggests the mode of cure, or even effects the cure itself, in cases of injury or disease. It is the divinity that stirs within us” of Stahl; the vis medicatrix naturæ of Hoffman and Cullen,g and the physicians of our own day. It is hence the strawberry travels from spot to spot, and the cod or the cuckoo, with a wider range, from shore to shore, or from climate to climate.ll

This Lecture was delivered January, 1813; and Mr. Keith on Tuesday, December 7, 1813, had a valaable paper read before the Linnæarı Society, in which, like the present system, he opposes Mr. Knight's bypothesis of gravitation as the cau-e of the peculiar stimulus and action of plants, and couceives that " the direction of the plumule and radicle of plants must be resolved into vegetable instinot, precisely analogous, and equally inexplicable with animal instinct."-See Thompson's Ann. of Philos, vol. lii. p. 71, In supplying the place of reason, it is perpetually assuming its semblance. Let us take an example or two from both the vegetable and the animal world.

Mr. Knight, while he seems desirous of resolving the principle of vegetable action into centripeta! force, has shown that the sap of plants, as it exists in the leaves of potatoes and mint, and the leaves and shoo's of the vine, possesses what he calls organizable mater: and when plunged in a moist and warm soil will produce bulbs or roots more or less perlect, or at least preserve and endeavour to extend life.Phil. Trans. 1816, p. 289. The whole, like the reproduction of polypes and worins from sections, ought rather w be resolved into the common law of Instinct, the aim of which is health, preservation, or repro duction: and hence the sap of planis seems as much alive as the blood of animals. Serics 1. Lecture xiv.

First Lines, vol. i. p. 91. 105. 11 In conformity with the general principles of his system, Dr. Darwin ascribes this extraordinary faculty also to the power of reason. “It is probable," says he, " that emigracions were at first undertaken as accl. dent directed by the more adventurous of their species, and learned from one another like the discoveries V mankind in navigation" --Zoon. seci. xvi. 11

or No. 13.

In order that the seeds of plants should produce and perfect their respective kinds, it is necessary that their shoots should rise to the surface of the earth to enjoy the benefit of light and air. Now in whatever direction the eye of a seed, from which germination first radiates, is placed, these shoots ascend equally to the surface, either in curved or straight lines, according as such ascent may be most easily accomplished. Mr. John Hunter sowed a quantity of pease and beans with their eyes placed in different directions, in a tub, which he afterward inverted, so that the bottom was turned uppermost while the mould was prevented from falling out by a fine net. And in order that the under surface might possess a superior stimulus of light and heat to the upper, he placed looking-glasses around the mouth of the tub in such a way that a much stronger light was reflected upon the inverted mould than that of the direct rays of the sun; while at the same time he covered the bottom of the tub with straw and mats to prevent the mould in this direction from being affected by solar influence. Yet the same instinctive law of ascent still prevailed. After waiting a considerable length of time, and perceiving that no shoots had protruded through the lower surface of the mould, he examined the contents of the tub, and found that they had all equally pressed upwards, and were making their way through the long column of mould above them, towards the reversed bottom of the vessel ; and that where the eyes had been placed downwards, the young shoots had turned round so as to take the same direction. As one experiment leads on to another, he determined to try the effect of placing other seeds of the same kinds in a tub to which a rotatory motion should be given, so that every part of it might be equally and alternately uppermost, and the seeds should have no advantage in one direction over another. Here, as we often behold in other cases, the instinctive principle of accommodation was baffled by a superior power, and the different shoots instead of ever turning round uniformly adhered to a straight line, except where they met with a pebble or any other resistance, when they made a curve to avoid such obstruction, and then resumed a straight line in the direction into which they were thereby thrown, without ever endeavouring to return to the original path.

Among animals we have various proofs of a like impulse, and we have also proofs of its being occasionally overpowered by a stronger cause. Thus, in cases of eruptive fever, there is an obvious effort of the instinctive principle to throw the morbific matter towards the surface of the body, where it can do least mischief. And where a deep-seated abscess has formed in the immediate neighbourhood of a cavity that cannot be opened into without great danger, as that of the chest or the stomach, the same instinctive principle of preservation leads forward the action in a different direction, though, as in the experiment of the bean-seeds in the inverted tub, with much greater labour and difficulty; and the abscess at length opens externally; and the remedial process of the formation of new living matter which immediately succeeds, commences under the same mysterious guidance. If, in the course of this common tendency to the surface, an obstructive cause be encountered, of superior force to the instinctive principle itself, the latter, as in the experiment of the beans exposed to the action of a rotatory motion, is overpowered, and the result is doubtful, and often fatal.

But these examples are general: let us advert to a few of a more particular nature. All the different species of birds, in constructing their nests, not only adhere to a peculiar plan, but, wherever they can obtain them, to peculiar kinds of materials : but if these materials be not to be procured, the accommodating power of the instinctive principle, as in the cases just related, directs them to others, and suggests the best substitutes. Thus the redbreast uniformly prefers oak-leaves as a lining for her nest, wherever she can acquire them; but if these be not to be had, she supplies the want by moss and hair. So where the bird is of small size, and the eggs are naturally numerous, the nest is always made proportionally warm, that the nestlings may

« PrécédentContinuer »