Popular Science Monthly/Volume 82/February 1913/Bergson's View of Organic Evolution
|BERGSON'S VIEW OF ORGANIC EVOLUTION|
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
THE French philosopher Henri Bergson has most appropriately chosen as the title of his book on development the name "Creative Evolution." As the name implies, to the inevitableness, the invariability of evolution as developed through physico-chemical laws, this philosophy adds the spontaneity, the indetermination of creation. The English translation of this book by Arthur Mitchell is a masterpiece of such work, and he is to be highly commended for the sympathetic manner in which the translation has been carried through.
All views of evolution divide naturally into two groups, the mechanistic—that all life can be accounted for through the application of the laws of physics and chemistry—and the vitalistic—that while the laws of physics and chemistry explain much, they do not explain all.
The principal radical views of these two groups are the following:
|Vitalistic||Creative Evolution (Bergson).|
The Neo-Lamarckians hold that characters acquired during the lifetime of an individual are transmitted to its offspring. The Neo-Darwinians deny this utterly, holding that the germ cell, the reproductive tissue, is set apart for its generative work while the animal is in its embryonic state, that is, the reproductive tissue is not the product of the animal's own soma cells, but of its parents' germ cells. This school of Neo-Darwinians explains evolution by the theory that the germ cells are continually changing in every possible direction permitted by their stage of development and that those of these changes shown forth in the adult animal or plant which are beneficial to the organism are selected by nature for preservation. To the adherents of the former school, environment gives rise to variations; to the adherents of the latter it merely selects. To the former the long neck of the giraffe is due to the necessity that successive generations get their food from higher and higher bushes, a process of stretching illustrated by the animals in Kipling's "Just So Stories"; to the latter, those changes in the germ cell leading to neck elongation in the adult were selected by nature in times of drought.
Teleology in its most radical form holds that life is carrying out a pre-arranged plan, that at the beginning everything was determined in detail and that all life is now following out the lines of that plan. Comparing this with the other two theories, the rabbits have long hind legs according to the Neo-Lamarckians because of the exercise they received when running to escape the fox; their ears likewise became longer because of the intentness with which they must guard against enemies. To the Neo-Darwinian the elongate ears and hind legs are due to changes in this direction in the germ cell, which changes nature selected by means of the fox who ate all individuals failing to make this change. To the teleologist it was planned in the beginning that as the fox became swifter the rabbit should likewise become swifter and more acute of hearing so that a proper balance should always be preserved between them.
Bergson's view of creative evolution is vitalistic in that it, with teleology, postulates a psychical force, which he calls the life impetus. But it differs from teleology especially in its belief that life is not bound by any prearranged plan, that it is free at all times to modify its course, to change its direction. Life, according to this view, is like a shell bursting as it flies, each fragment again bursting, and so on. The life impetus is thus continually dividing. Just as the way a shell bursts depends both upon the explosive force of the powder and the resistance of the metal surrounding it, so the direction of life depends upon the unstable balance of tendencies which it bears within itself and the resistance it meets with from inert matter. It is as if the vital impetus were trying to graft on the invariableness of matter the largest possible amount of instability.
According to the view of creative evolution, then, environment is a force evolution must reckon with, but not its cause, as with the mechanists, while adaptation of the organism to its environment will explain the sinuosities of the course of evolution, but not the general direction and still less the cause of the movement itself.
The problem confronting this vital impetus as it enters matter is somewhere to gather energy with which to counteract the retarding force of matter. At the surface of this earth the most available source of energy is the sun's rays. So the problem before life was this—to store this energy in suitable reservoirs so that it could be drawn upon at any time and for any need such as movement or reproduction. It succeeded in this by causing the kinetic power of the sun's rays to break up the inorganic compounds into their separate elements and then recombine them into the potential energy of organic foodstuffs. At first, doubtless, an organism thus gathered for itself the energy which it later expended in free movements; this form may be symbolized in a crude way by the infusorian, Euglena. This organism expends kinetic energy in motion like any animal, but in addition to the ordinary animal method of deriving potential energy from plant reservoirs it likewise stores up potential energy for itself by the direct action of the sun's rays on its chlorophyll. But in the course of higher development it was found that these two functions, that of storing up energy and its expenditure in free movements, were incompatible in the same organism. There thus opened out before the organism two lines of development, one of greater movement, but with all the hazard of an uncertain food supply, the other of fixity, but with a certainty of food supply; the former resulted in the animal kingdom, the latter in the vegetable.
Since, however, these two kingdoms are branches of the same life impetus each contains something of the other. The difference lies merely in the tendencies upon which each lays emphasis, while it leaves the other tendencies lying dormant. So that plants and animals can not be defined by mutually exclusive characters, but rather by the accentuation of certain tendencies. Plants take their food as a rule from the inorganic, animals from the organic; as a result plants are usually fastened to the earth, immobile; animals get their food through movement. As a consequence of this differing method of food getting the plant cell surrounds itself with a hard coat of cellulose through which external stimuli can with difficulty affect the organism, and there is hence made possible but a very slight consciousness. Since to the animal cell movement is essential to food getting, it can not completely encase itself in a hard external skeleton; it thus follows that external stimuli readily affect the organism and there is hence rapidly developed an ever higher type of consciousness.
Consciousness, as used by Bergson, is not limited to self-consciousness, but is the kind of consciousness that Jennings in his "Behavior of Lower Organisms" is inclined to believe is possessed by all animals from the highest to the lowest. Bergson relates it to mobility. "The humblest organism is conscious in proportion to its power to move freely."
The elements into which a tendency splits do not possess the same power to evolve. The truly elementary tendencies continue to evolve, leaving behind the residual, split-off tendencies. This is illustrated in the development of the plant kingdom, where it is the carbon-fixers which carry on the main line of evolution.
Along the animal pathway, three of the main branches are those of the mollusks, arthropods and vertebrates. During the middle Paleozoic all had run into the blind alleys of stagnancy, of torpor, since most forms of these phyla had become enclosed in a hard external skeleton; but before this condition had become universal, some of the arthropods assumed, instead of the hard external skeleton of the crustacean, the soft one of the insect, and among the vertebrates the armored fish gave place to the unarmored. Bergson here makes one of his most suggestive contributions, for he makes intellect and instinct divergent instead of linear characteristics. Intellect is not derived from instinct, but they are both present in all life. The former is emphasized by the vertebrates, reaching its culmination in man; the latter is especially developed by the arthropods and finds its highest expression in the Hymenoptera—bees, wasps and ants. The awakening from torpor could be effected in two ways; life, i. e., consciousness launched into matter, could fix its attention either upon its own movement or upon the matter it was passing through, and it would thus be turned either in the direction of intuition, or of intellect. Apparently, on the side of intuition consciousness could not go far; it found itself so restricted by its envelope that intuition had to shrink into instinct, i. e., to embrace only that portion of life upon which its continued well-being depended. Instinct is a prolongation of the life principle (vital impulse). We call that the life principle which in a living body coordinates the thousands of cells to work towards a common end and to divide the labor of feeding, reproduction and preservation among them, but we call that instinct which causes the bees of a hive to work towards a common end, and to divide the labor of feeding, reproduction and preservation among them.
The most essential of the primary instincts are really vital processes. Instinct only carries further the work by which life organizes matter. When the little chick is breaking its shell with a peck of its beak it is acting by instinct, and yet it merely carries on the movement which has borne it through its embryonic life. When the digger-wasp, Ammophila, stings its caterpillar victim in just the right places to ensure paralysis without death it acts by instinct, it must not be considered to have any knowledge like that of the learned entomologist who would know the vulnerable places from the outside—from detailed observations of all parts of the caterpillar body. The insect's knowledge, instinctive, proceeds from its inner identification with the same life principle as that of the caterpillar—from a sympathy (in the etymological sense of the word) between the two organisms which teaches the insect from within the vulnerability of its victim, whereas the intelligence of the entomologist goes all around the caterpillar instead of entering into it, making itself one with it.
On the other hand, consciousness concentrating its attention upon the matter it was passing through succeeded in evading the barriers raised by it, and now in man, freed to some extent from matter, it can turn inwards on itself and awaken the powers of intuition which still slumber within it. Intuition as thus used is instinct that has become disinterested, self-conscious, capable of reflecting upon its object.
Bergson makes freedom the corner-stone of his theory. The vital impetus has for its goal the acquirement of an ever fuller volume of free, creative activity. Man shows that forth in himself in the creation, improvement and pursuit of ideals. He follows no prescribed path; he is perfectly free to choose, except that he may not go contrary to the broad course of evolution, i. e., the direction of flow of the vital impetus.
While consciousness (vital impetus) is thus creation and choice, it is also memory. Beings advance in time, treading, as it were, upon a carpet which they weave with whatever colors and texture they wish, but they are ever rolling this carpet up behind them and carrying it with them. Thus all of the past is preserved, though not indeed all as self-conscious memories. It is this whole past which, "gnawing into the future, swelling as it advances," Bergson calls duration. The biologic law of recapitulation takes cognizance of a part of this memory.
Thus instead of a finalistic or a mechanistic universe with its course known or foreseeable, Bergson postulates one creating itself endlessly along an indeterminable course, constantly enlarging with the volume of its past experiences.