13 Nov 2009

Non-Resembling Reproduction. Creative Evolution. Bergson. Ch.1 Part 8. The Quest of a Criterion

by Corry Shores
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Non-Resembling Reproduction

Henri Bergson

Creative Evolution

Évolution Créatrice

Chapter 1

The Evolution of Life – Mechanism and Teleology

Chapitre Premier

De l’évolution de la vie. – Mécanisme et finalité.

8. The Quest of a Criterion
8. Recherche d'un critérium.

Bergson rejects mechanism. He follows finalism only so far. Then he breaks from it. He explained previously: we are not evolving toward any destination. But, we are moving forward. For, evolution is creative.

§55 Evolving Differences

Live evolved. At its origin was an impetus. It has continued since.

There are many evolving species. The one creative evolutionary impetus diverged into a multiplicity of concurrent developmental tendencies. Some species became extinct. They were incompatible with the others at that time.

We said of life that, from its origin, it is the continuation of one and the same impetus, divided into divergent lines of evolution. Something has grown, something has developed by a series of additions which have been so many creations. This very development has brought about a dissociation of tendencies which were unable to grow beyond a certain point without becoming mutually incompatible. [56c emphasis mine]

Nous disions que la vie, depuis ses origines, est la continuation d'un seul et même élan qui s'est partagé entra des lignes d'évolution divergentes. Quelque chose a grandi, quelque chose s'est développé par une série d'additions qui ont été autant de créations. C'est ce développement même qui a amené à se dissocier des tendances qui ne pouvaient croître au delà d'un certain point sans devenir incompatibles entre elles. [57-58]

There are other ways to conceive evolution. We might think of just one thing that evolved without any companions. This process would have only one dimension: a single line of development. Or, perhaps we conceive of evolution this way: there are many species evolving at the same time, but none along a linear continuum. This would also be one dimensional. At every moment there is an extension of different species. But they would not extend through a temporal development. For, there would in this second case just be continuous lines of evolution.

Evolution, however, is not one-dimensional. It has “actually taken place through millions of individuals, on divergent lines, each ending at a crossing from which new paths radiate, and so on indefinitely” (56-57 emphasis mine).

Bergson’s thesis is that there is one driving impetus for all the many lines of development. [As a driving force, it is something of a psychological nature]. Hence “they must keep something in common in spite of the divergence of their effects, as school-fellows long separated keep the same memories of boyhood. Roads may fork or by-ways be opened along which dissociated elements may evolve in an independent manner, but nevertheless it is in virtue of the primitive impetus of the whole that the movement of the parts continues” (57a.b).

So all the divergent paths share a common driving force. We will see evidence of it in each particular species. For example, the internal organs of different species will bear similarities: “Something of the whole, therefore, must abide in the parts; and this common element will be evident to us in some way, perhaps by the presence of identical organs in very different organisms” (57b).

We will now draw a sharp contrast between classical mechanism and creative evolution. The distinction regards different ways to produce likenesses.

[Consider first that bread is made round the world. The same laws of chemistry are used each time. The result is that bread is roughly similar no matter where you go (or else we would not call it bread). So here a similar thing (bread) is produced by a similar means (baking dough).

Now let’s think about evolution. Organisms were very similar and simple in the beginning. Gradually they diverged, developed, and diversified into the variegated plurality of species we know today. Note how many plants and animals reproduce by some sort of fertilization process. Let’s consider the simpler life forms preceding plants and animals. Probably there were ancient organisms lacking plant and animal traits. But evolving from this pool of simple life forms were two diverging lines of development: one tending toward being more plantlike and the other toward being more animal-like. Now try to imagine organisms that have not yet evolved enough to be classified as either plants or animals. Can we even conceive of how so simple an organism would reproduce using fertilization? It’s difficult. So Bergson assumes that both plants and animals developed their own form of fertilization independently from each other, after they went down their divergent lines of evolution. And hence] Bergson’s theory is that there is a common evolutionary impulse shared by drastically diverging lines of development.

A mechanist would explain these similarities a different way. They would not result from a common evolutionary impulse. Mechanists only consider mechanical processes. For them, the cause lies behind the effect. So things are not all unified by a common driving force, whether towards a final end or not. Under this mechanist view, it would only be by accident if different lines of evolution independently develop similarities: “evolution must then have occurred through a series of accidents added to one another, each new accident being preserved by selection if it is advantageous to that sum of former advantageous accidents which the present form of the living being represents” (57c). So it is highly unlikely that a similarity between species [such as plant and animal fertility] results from mechanistic causes. He writes: “The more two lines of evolution diverge, the less probability is there that accidental outer influences or accidental inner variations bring about the construction of the same apparatus upon them, especially if there was no trace of this apparatus at the moment of divergence” (57c?).

Bergson’s theory of the universal evolutionary impulse however does explain such phenomena. [Now consider again plant and animal fertilization. Each one is a very different sort of fertilization. They came about in very different ways. We cannot use a common mechanistic principle to explain the very different ways they originated. So,] creative evolutionary theory regards the independently-evolved similarities as being apparatuses that are alike but that were produced by very different means. However, mechanistic theories would say that there is probably a common cause for a feature shared by different species. Hence in mechanism, these similarities are likenesses produced by like means. Thus, Bergson could disprove mechanism if he shows that likeness can be produced by unlike means on account of a common impetus.

Pure mechanism, then, would be refutable, and finality, in the special sense in which we understand it, would be demonstrable in a certain aspect if it could be proved that life may manufacture the like apparatus, by unlike means, on divergent lines of evolution; and the strength of the proof would be proportional both to the divergency between the lines of evolution thus chosen and to the complexity of the similar structures found in them. [57-58, emphasis mine]

Le pur mécanisme serait donc réfutable, et la finalité, au sens spécial où nous l'entendons, démontrable par un certain côté, si l’on pouvait établir que la vie fabrique certains appareils identiques, par des moyens dissemblables, sur des lignes d'évolution divergentes. La force de la preuve serait d'ailleurs proportionnelle au degré d'écartement des lignes d'évolution choisies, et au degré de complexité des structures similaires qu'on trouverait sur elles. [59bc]

§56 Adapting Machines

Mechanists might say that it was not purely coincidence that there is so much similarity between the diverse species. Rather, each creature is part of a line of development. But, they might add, throughout their generational alterations, each different species faces very similar conditions. [For example, the sun shines on the surface of the earth, so many surface-dwelling animals have eyes.] Each species adapts to the similar conditions. Hence mechanists might argue that we should not be surprised when evolutionary adaptations would be similar.

But not all biologists see adaptation the same way. [Consider the example of vision. Some might say that the sun’s light directly causes the organism to evolve eyes, as though the light impresses upon the skin, which responds by creating light-sensing organs. Others might say that there are various mutations, and those with sensitivity to light out-competed those species which could not see. And gradually vision developed.] So there are some biologists who think adaptation comes about from a stimulus’ direct influence on the organism, while others (of a more Darwinist persuasion) say that adaptation results indirectly: natural selection favors those mutations that are more fit to the given conditions.

[Consider that in the first case, the sunlight added vision to the creature, while in the second case, the sunlight subtracted those beings which could not see. Hence,] some biologists think thatpositive influences cause adaptation by producing variations, while other think that it results from negative influences that eliminate variations.

Nonetheless, both cases share something in common: outer conditions cause the adaptation. It is like a cause-effect mechanism. Hence biologists on both sides are mechanists in this way.

Bergson will now give a general presentation of his arguments against mechanistic adaptation.

§57 Darwin’s Accident

Consider first the positive direct thesis of adaptation. Conditions directly cause changes in the species, [like light stimulating animals to grow eyes]. In this case, we can explain the similarities on the grounds that there is a common source for all the similar variations across the wide range of species. But now instead consider the Darwinist thesis: there are random mutations, and those that are sufficiently adapted to circumstances survive the others. [So recall the example of light under this Darwinian theory. Let’s imagine all the different lines of evolution before they obtained vision. Somehow each one had the same random mutation that caused each to have symmetrical eye-pairs. As well, they share many other internal organs. Are there not infinitely many other ways that an organism can take-in nutrition and eliminate waste? Why do all have very similar digestive tracks? Are conditions really so similar that every animal would evolve nearly identical digestive organs? Given all the other possibilities, it seems far too unlikely. So] this Darwinist thesis seems untenable when we consider that such profound similarities between species all came-about independently.

An accumulation of accidental variations, such as would be necessary to produce a complex structure, requires therefore the concurrence of an almost infinite number of infinitesimal causes. Why should these causes, entirely accidental, recur the same, and in the same order, at different points of space and time? [59c]

Une accumulation de variations accidentelles, comme il en faut pour produire une structure compliquée, exige le concours d'un nombre pour ainsi dire infini de causes infinitésimales. Comment ces causes, toutes accidentelles, réapparaîtraient-elles les mêmes, et dans le même ordre, sur des points différents de l'espace et du temps? [61a]

Hence, “The struggle for life and natural selection can be of no use to us in solving this part of the problem, for we are not concerned here with what has perished, we have to do only with what has survived” (60-61).

§58 Can a Machine Wander?

Recall the principle of mechanism: “the same causes produce the same effects” (60b). Mechanists do not work backward, saying that the same effects must have the same causes, [as Bergson would like to do with similarities between divergent evolutionary lines]. But Bergson argues that we may assume that in evolution, similar outcomes result from similar causes. [For Bergson, this is the common evolutionary impetus]. He will show that the fact that two species have the same organs is not a matter of random chance. The mechanist would say it is random. Bergson analogizes the random path of development with the example of two people wandering aimlessly. Eventually they meet. This is no surprise; we expect them to at some point. Let’s suppose we draw a line that follows each walker’s wanderings. How likely is it that both random walks are so similar that we may superpose them and match them identically? Now, their paths could be very complex. But consider how unfathomably complex one internal organ is. And it will be similar with another species’ same organ. The development of each evolutionary line will be different and it will create something profoundly complex. But it is as though both were being guided by a common impetus. It cannot just be coincidence that all animals have such similar internal organs. (60c)

§59 The Positive Thesis is Missing Something

We just examined the Darwinian thesis that there are random accidental evolutionary changes. And we found that such an accidental basis cannot explain all the evolutionary similarities, because there would be far too many unlikely coincidences. Now Bergson will examine the other thesis, the positive one. According to this view, species adapt because external conditions directly force the species to comply with its environment. “Adaptation [...] is not merely elimination of the unadapted; it is due to the positive influence of outer conditions that have moulded the organism on their own form” (60d). In the first theory, similar causes produce similar effects. In this other hypothesis, the similarities between the effects are produced by similarities in the causes (60d). However, Bergson claims that this hypothesis is based on a semantical confusion regarding the term “adaptation” (61).

§60 Evolution is Neither Wine nor Line

We confuse two meanings for ‘adaptation’ when we follow the positive theory. Consider the first meaning with an example. We pour water and wine into a glass. The fluids mix and take the form of the glass itself. We might say that the liquid is ‘adapting’ to the structural conditions of the glass. But this sort of adaptation is really just a mechanical way that fluids adjust to their containers. In this case, the shape of the glass already exists, and it forces its contours upon the water/wine mixture.

But consider instead the adaptation of an organism. [Image creatures that have been forced into a colder region. Some change the way they build their shelters to better protect them from the cold. Others hibernate. Some develop migration patterns. Others change their diet, or the way they raise their young. None of these adaptations are like the imprint of coldness, like how the watered wine takes-on the imprint of the glass containing it.] When organisms adapt, there is no concrete ‘form’ to their environment. There are conditions. And the creature must form itself in its own way in order to adapt to those conditions. Their new changes will not resemble the conditions like how the watered wine resembles the glass. [Migration does not resemble coldness]. Rather, the conditions are a ‘call,’ and each species independent adaptation is the ‘response’.

The circumstances are not a mould into which life is inserted and whose form life adopts: this is indeed to be fooled by a metaphor. There is no form yet, and life must create a form for itself, suited to the circumstances which are made for it. It will have to make the best of these circumstances, neutralize their inconveniences and utilize their advantages, in short, respond to outer actions by building up a machine which has no resemblance to them. Such adapting is not repeating, but replying, an entirely different thing. (61c, underline and boldface mine)

Les conditions ne sont pas un moule où la vie s'insérera et dont elle recevra sa forme : quand on raisonne ainsi, on est dupe d'une métaphore. Il n'y a pas encore de forme, et c'est à la vie qu'il appartiendra de se créer à elle-même une forme appropriée aux conditions qui lui sont faites. Il va falloir qu'elle tire parti de ces conditions, qu'elle en neutralise les inconvénients et qu'elle en utilise les avantages, enfin qu'elle réponde aux actions extérieures par la construction d'une machine qui n'a aucune ressemblance avec elles. S'adapter ne consistera plus ici à répéter, mais à répliquer, ce qui est tout différent. (63a)

Now consider a geometry problem. [For example, we know two angles of a triangle, 30 and 60 degrees. On that basis we want to find the third.] We are given certain conditions. And our answer ‘adapts’ to them. [The third is 90 degrees, because that is all the angular ‘room’ left that the other angles leave us.] But this is different than the mechanical adaptation of fluids in a glass. When we solve a geometry problem, we had to engage with the conditions using our minds, and find a solution by working with our mental tools. But still this is unlike natural evolution, because it presupposes that there is some final answer and an intelligible logic in the mathematics of geometry. We only need to find that pre-existing (a priori) solution using logical analysis. So Bergson’s evolution is neither like filling a glass nor solving a geometry problem. If evolution were just a passive molding, then all the possible forms are already given in the conditions, waiting for creatures to mold to them. This cannot explain then how new forms are created. But if evolution were like actively solving a geometry problem using logic, then we are ascribing too much of a human-like intelligence to the world [see §53 for Bergson's critique of this sort of finalism]. But often times people slip from one such meaning of adaptation to the other, switching as soon as the one ceases to be effective.

Images from the English translation [click to enlarge]:

Images from the original French [click to enlarge]:

Bergson, Henri. L'Évolution Créatrice. Ed. Felix Alcan. Paris: Librairies Félix Alcan et Guillaumin Réunies, 1908. Available online athttp://www.archive.org/details/levolutioncreatr00berguoft

Bergson, Henri. Creative Evolution. Transl. Arthur Mitchell. London: MacMillan and Co., 1922. Available online at:http://www.archive.org/details/creativeevolutio00berguoft

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