Creative Evolution — Henri Bergson (trans. Arthur Mitchell, 1911)

In thus submitting the various present forms of evo- lutionism to a common test, in showing that they all strike against the same insurmountable difficulty, we have in no wise the intention of rejecting them altogether. On the contrary, each of them, being supported by a considerable number of facts, must be true in its way. Each of them must correspond to a certain aspect of the process of evolution. Perhaps even it is necessary that a theory should restrict itself exclusively to a particular point of view, in order to remain scientific, i.e. to give a precise direction to researches into detail. But the reality of which each of these theories takes a partial view must transcend them all. And this reality is the special object of philosophy, which is not constrained to scientific pre-

' Giard, Controixraa Iraru/omufsi, Parui, 1904, p. 147.

M Result of the Discussion 85

86 CREATIVE EVOLUTION [OHAP.

then there is the possibility, as we shall explain further on, that the part played by chance is much greater in the variation of plants than in that of animals, because, in the vegetable world, function does not depend so strictly on form. Be that as it may, the neo-Darwinians are inclined to admit that the periods of mutation are deter- minate. The direction of the mutation may therefore be so as well, at least in animals, and to the extent we shall have to indicate.

We thus arrive at a hypothesis like Eimer'e, according to which the variations of differGnt characters continue from generation to generation in definite directions. This hypothesis seems plausible to us, within the limits in which Eimer himself retains it. Of course, the evolution of the organic world cannot be predetermined as a whole. We claim, on the contrary, that the spontaneity of life is mani- fested by a continual creation of new forms succeeding others. But this indetermination cannot be complete; it must leave a certain part to determination. An organ like the eye, for example, must have been formed by just a continual changing in a definite direction. Indeed, we do not see how otherwise to explain the likeness of structure of the eye in 8i)ecie8 that have not the same history. Where we differ from Eimer is in his claim that combinations of physical and chemical causes are enough to secure the result. We have tried to prove, on the contrary, by the example of the eye, that if there is "orthogenesis" here, a psychological cause intervenes.

Certain nco-Lamarckians do indeed resort to a cause of a psychological nature. There, to our thinking, is one of the most solid positions of neo-Lamarckism. But if this cause is nothing but the conscious effort of the in- dividual, it cannot operate in more than a restricted num- ber of cases — at most in the animal world, and not at all

Result of the Discussion 87

in the v^etable kingdom. Even in animals, it will act only on points which are under the direct or indirect con- trol of the will. And even where it does act, it is not clear how it could compass a change so profound as an increase of complexity: at most this would be conceivable if the acquired characters were regularly transmitted so as to be added together; but this transmission seems to be the exception rather than the rule. A hereditary change in a definite direction, which coutinuea to accumulate and add to itself so as to build up a more and more complex machine, must certainly be related to some sort of effort, but to an effort of far greater depth than the individual effort, far more indepeodent of circumstances, an effort common to most representatives of the same species, inherent in the germs they bear rather than in their sub- stance alone, an effort thereby assured of being passed on to their descendants.

So we come back, by a somewhat roundabout way, to the idea we started from, that of an original impetus of life, passing from one generation of germs to the fol- lowing generation of germs through the developed organ- isms which bridge the inter\-al between the generations. This impetus, sastained right along the lines of evolution among which it gets divided, is the fundamental cause of variations, at least of those that are regularly passed on, that accumulate and create new species. In general, when species have begun to diverge from a common stock, they accentuate their divergence as they progress in their evolution. Yet, in certain definite points, they may evolve identically; in fact, they must do so if the hypothesis of a common impetus be accepted. This is just what we shall have to show now in a more precise way, by the same example we have chosen, the fonnation of the eye in

molluscs and vertebrates. The idea of an "original impetus," moreover, will thus be made clearer.

Two points are equally striking in an organ like the eye: the complexity of its structure and the simplicity of its function. The eye is composed of distinct parts, such as the sclerotic, the cornea, the retina, the crystalline lens, etc. In each of these parts the detail is infinite. The retina alone comprises three layers of nervous elements — multipolar cells, bipolar cells, visual cells — each of which has its individuality and is undoubtedly a very compli- cated organism: so complicated, indeed, is the retinal membrane in its intimate structure, that no simple de- scription can give an adequate idea of it. The mechanism of the eye is, in short, composed of an infinity of mechan- isms, all of extreme complexity. Yet vision is on- simple fact. As soon as the eye opens, the visual act is effected. Just because the act is simple, the slightest negligence on the part of nature in the building of the infinitely com- plex machine would have made vision impossible. This contrast between the complexity of the organ and the unity of the function is what gives us pause.

A mechanistic theory is one which means to show us the gradual building-up of the machine under the influence of external circumstances intervening either directly by action on the tissues or indirectly by the selection of better- adapted ones. But, whatever form this theory may take, supposing it avails at all to explain the detail of the parts, it throws no light on their correlation.

Then comes the doctrine of finality, which says that the parts have been brought together on a preconceived plan with a view to a certain end. In this it likens the labor of nature to that of the workman, who also pro- ceeds by the assemblage of parts with a view to the real- ization of an idea or the imitation of a model. Mechanism,

I.l

The Vital Impetus

here, reproaches finalism with its anthropomorphic charac- ter, and rightly. But it fails to see that itself proceeds accordiiig to this method — somewhat mutilated! True, it has got rid of the end pursued or the ide^l model. But it also holds that nature has worked like a human being by bringing parts together, while a mere glance at the development of an embrj-o shows that hfe goes to work in a very different way. Life does not proceed by the as- sodalion and addition of elements, biU by dissociation and division.

We must get beyond both points of view, both mechanism
and finalism being, at bottom, only standpoints to which
the human mind has been led by considering the work of
man. But in what direction can we go beyond them?
We have said that in analyzing the structure of an organ,
we can go on decomposing for ever, although the function
of the whole is a simple thing. This contrast between
the infinite complexity of the organ and the extreme
simplicity of the function is what should open our eyes.

In general, when the same object appears in one aspect as simple and in another as infinitely complex, the two as- pects have by no means the same importance, or rather tlio same degree of reality. In such cases, the simplicity be- longs to the object itself, and the infinite complexity to the views we take in turning around if, to the symbols by which our senses or intellect represent it to us, or, more generally, to elements of a different order, with which we try to imitate it artificially, but with which it remains incommensurable, being of a different nature. An artist of genius has painted s figure on his canvas. We can imitate his picture with many-colored squares of mosaic. And we shall reproduce the curves and shades of the model so much the better as our squares are smaller, more numerous and more varied in tone. But an infinity of elements infinitely small,

presenting an infinity of shades, would be necessary to obtain the exact equivalent of the figure that the artist has conceived ss a simple thing, which he has wished to transport as a whole to tlie canvas, and which is the more complete the more it strikes us as the projection of an indivisible intuition. Now, suppose our eyes so made that they cannot help seeing in the work of the master a mosaic effect. Or suppose our intellect so made that it cannot explain the appearance of the figure on the canvas except as a work of mosaic. We should then be able to speak simply of a collection of little squares, and we should be under the mechanistic hypothesis. We might add that, beside the materiality of the collection, there must be a plan on which the artist worked ; and then we should be expressing ourselves as finalists. But in neither case should we have got at the real process, for there are no squares brought together. It is the picture, i.e. the simple act, projected on the canvas, which, by the mere fact of entering into our perception, is decomposed before our eyes into thousands and thousands of little squares which present, as recomposed, a wonderful arrangement. So the eye, with its marvelous complexity of structure, may be only the simple act of vision, divided for us into a mosaic of cells, whose order seems marvelous to us because we have conceived the whok as an assemblage.

If I raise my hand from A to B, this movement appears to me under two aspects at once. Felt from within, it is a simple, indivisible act. Perceived from without, it is the course of a certain curve, AB. In this curve I can dis- tinguish as many positions as I please, and the line it- self might be ilelincd as a certain mutual coordination of these positions. But the [wsitions, infinite in number, and the order in which they are connected, have sprung automatically from the indivisible act by which my hand

The Vital Impetus

has gone from A to B. Mechanism, here, would consist in seeing only the positions. Finalisra would take their order into account. But both mechanism and finalism would leave on one side the movement, which is reality itself. In one sense, the movement is more than the positions and than their order; for it is sufficient to make it in its indivisible simplicity to secure that the infinity of the successive positions as also their order be given at once — with something else which is neither order nor position but which is essential, the mobility, But, in another sense, the movement is leas than the series of positions and their connecting order; for, to arrange points in a certain order, it is necessary first to conceive the order and then to realize it with points, there must be the work of assemblage and there must be intelligence, whereas the simple movement of the hand contains noth- ing of either. It is not intelligent, in the human sense of the word, and it is not an assemblage, for it is not made up of elements. Just so with the relation of the eye to vision. There is in vision more than the component cells of the eye and their mutual coordination: in this sense, neither mechanism nor finalism go far enough. But, in another sense, mechanism and finalism both go too far, for they attribute to Nature the most formidable of the labors of Hercules in holding that she has exalted to the simple act of vision an infinity of infinitely complex ele- ments, whereas Nature has had no more trouble in making an eye than I have in lifting my hand. Nature's simple act has divided itself automatically into an infinity of elements which are then found to be coordinated to one idea, just as the movement of my hand has dropped an infinity of points which are then found to satisfy one equation. We find it very hard to see things in that light, because

[CRAP.