[Search Blog Here. Index-tags are found on the bottom of the left column.]
[Central Entry Directory]
[Bergson, Entry Directory]
[Other entries in the Bergson Creative Evolution series]
[Paragraph headings are my own.]
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.
11. De Vries and Sudden Variation
11. De Vries et la variation brusque
Mechanists think that evolution happens by means of random variations.
Now Bergson will address the other theory of random evolution. According to this theory, there are sudden mutations. Hugo de Vries is responsible for this idea.
§68 Unlikely Leaps of the Eye
Bergson recalls the similarities between mollusk and invertebrate eyes [see §64]. Let’s begin first with the theory of insensible variations. It would say that both mollusk eyes and invertebrate eyes developed little-by-little, but each time by random. It is hard to imagine how two independent lines of develop would coincide, when each would require an incalculable number of tiny coinciding variations. So to say that both mollusks and invertebrates developed eyes by ‘sudden leaps’ makes it more conceivable that the changes were random. Bergson also discussed previously another problem with the theory of insensible variations. The eye has very many different parts. If there is a small variation in one part, without there being variations in the other, then the new variation would not better serve the eye’s functioning. And hence there would be no cause for this trait to be passed-on. But if there are sudden variations in all the parts, then we can imagine how the advance would better adapt the species to its circumstances. Yet if there was one great variation in just one part, then the eye would function more poorly. So the mutation would need to change all the parts at once. Yet this again requires that chance surmount grave unlikelihood.
§69 Correlation as Final Causation
The theory of sudden variation is supported most by experiments in botany. But plants can take-on many different variations without that profoundly changing their functioning. So a profound change in the form of the leaf for example will not require major changes throughout the rest of the plant in order for it to maintain its proper functioning. This is not so for the more complex systems of animals, which are very easily thrown out of balance by the slightest changes.
Evolutionists often speak of correlated variations. But we see that to do so is to suppose some guiding force that coordinates the changes. That would be a form of finalism, then, even though the supposed basis is mechanistic.
From the English translation:
From the original French:
No comments:
Post a Comment