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While we wait for someone who knows more about Lamarckism than I do to extract a self from it, I'll have a go myself.
Lamarck saw evolution involving two separate processes. One was "complexifying," the generation of new features and capabilities by a faculty that he referred to as "a subtle fluid" located in the bodies of living creatures. The other process was the harnessing of such novel features, through use and disuse, to adapting creatures more closely to their environments. "Complexifying" generated variation, use and disuse winnowed it and shaped it to improve the fit between a creature and its environment. Superficially, complexifying resembles mutation in generating variation, use and disuse resemble natural selection in how they relate to variation.
Use and disuse were something the creature itself did. By applying aspects of new features to life's problems the creature could reinforce those aspects, either by developing a new habit or by reinforcing the tissues involved, as a giraffe by stretching further its already long neck could make it longer still. Both habits and enhanced tissues would be inherited by the creature's progeny.
Again, if we assume that creatures like us are bound to identify with the obvious success of evolution and wish to participate in its progress, our opportunity to do so can come only through use and disuse. Lamarck made it clear we individually have no access to whatever is responsible for "complexifying. "
Use and disuse have a wonderfull puritan quality to them. We are to dutifully exercise those talents and tissues that make for success, while shunning those that are not useful but merely pleasurable. Heaven forbid that through entertaining such fruitless pleasures we build them into future generations. So Lamarckism lays heavy obligations onto the individual: to exercise those talents and tissues that are useful, to shun those that are frivolous, and to appreciate the difference.
Lamarck's specialty was invertebrates. He didn't have to worry about his theory turning them into puritans. It may not even have occurred to him that, taken to its logical conclusion, his theory could turn them into Calvinists! But that, or something like that, is implied by some of us bearing within us the faculty of "complexifying, and some of us not. That, and that alone, is what carries evolution forward, that is the only significant contribution one could make to the progress of evolution. Use and disuse are merely lateral movements adapting creatures to this or that environment. But Lamarck presents complexifying as a gift from the gods: we either have it and are blest, or we don't and our lives are blighted.
Lamarck's theory has been discounted because today's science knows of no mechanism by which attributes acquired during life can be passed on to progeny. As far as the self implied by Lamarckism goes, though, I think the natural world bears it out fairly well. The birds and the bees all seem busy developing their talents and adapting to their environments. It seems inadequate in only one instance: us. We clearly all have a creative faculty, we each possess the ability to complexify. Which means that faculty is no longer an inscrutable "subtle fluid" but something we should be able to identify in ourselves. And once we do we'll know what it is that drives all of evolution.
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By Robert Chambers, a well-known publisher of the time
Vestiges of the Natural History of Creation, published anonymously 1844.
(Extract from this enormously influential book concerning the mechanism of evolution.)
Early in this century, M. Lamarck, a naturalist of the highest character, suggested an hypothesis of organic progress which deservedly incurred much ridicule, although it contained a glimmer of the truth. He surmised, and endeavoured, with a great deal of ingenuity, to prove, that one being advanced in the course of generations to another, in consequence merely of its experience of wants calling for the exercise of its faculties in a particular direction, by which exercise new developments of organs took place, ending in variations sufficient to constitute a new species. Thus he thought that a bird would be driven by necessity to seek its food in the water, and that, in its efforts to swim, the outstretching of its claws would lead to the expansion of the intermediate membranes, and it would thus become web-footed. Now it is possible that wants and the exercise of faculties have entered in some manner into the production of the phenomena which we have been considering; but certainly not in the way suggested by Lamarck, whose whole notion is obviously so inadequate to account for the rise of the organic kingdoms, that we only can place it with pity among the follies of the wise. Had the laws of organic development been known in his time, his theory might have been of a more imposing kind. It is upon these that the present hypothesis is mainly founded. I take existing natural means, and shew them to have been capable of producing all the existing organisms, with the simple and easily conceivable aid of a higher generative law, which we perhaps still see operating upon a limited scale. I also go beyond the French philosopher to a very important point, the original Divine conception of all the forms of being which these natural laws were only instruments in working out and realizing....Such a regularity in the structure, as we may call it, of the classification of animals, as is shewn in their systems, is totally irreconcilable with the idea of form going on to form merely as needs and wishes in the animals themselves dictated. Had such been the case, all would have been irregular, as things arbitrary necessarily are. But, lo, the whole plan of being is as symmetrical as the plan of a house, or the laying out of an old-fashioned garden! This must needs have been devised and arranged for beforehand. And what a preconception or forethought have we here! Let us only for a moment consider how various are the external physical conditions in which animals live - climate, soil, temperature, land, water, air - the peculiarities of food, and the various ways in which it is to be sought; the peculiar circumstances in which the business of reproduction and the care-taking of the young are to be attended to - all these required to be taken into account, and thousands of animals were to be formed suitable in organization and mental character for the concerns they were to have with these various conditions and circumstances - here a tooth fitted for crushing nuts; there a claw fitted to serve as a hook for suspension; here to repress teeth and develop a bony net-work instead; there to arrange for a bronchial apparatus, to last only for a certain brief time; and all these animals were to be schemed out, each as a part of a great range, which was on the whole to be rigidly regular: let us, I say, only consider these things, and we shall see that the decreeing of laws to bring the whole about was an act involving such a degree of wisdom and device as we only can attribute, adoringly, to the one Eternal and Unchangeable....the idea that any of the lower animals have been concerned in any way with the origin of man - is not this degrading?
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Lamarck is representative of the tradition of science that preceded Positivism with its emphasis on elemental matter and its exclusion from consideration of mind and volition. Lamarck would therefore be a useful starting point, along with his contemporary Erasmus Darwin, Charles Darwin's grandfather, for a Post Positivist tradition of evolutionary theory.
To account for how the invertebrate species he studied appeared to generate one another in succession, while becoming better adapted to their environments, Lamarck proposed two processes. One was a complexifying process leading to new capabilities, due he supposed to a "subtle fluid" in creatures' bodies, employing a catch phrase of 18th century science. The other process was adaptation to the environment through the use and disuse by individual creatures of those capabilities. The changes wrought in creatures' bodies by that use and disuse Lamarck supposed got inherited in progeny.
"Subtle fluid'" didn't cut any ice with Positivists like Charles Darwin, who replaced both of Lamarck's processes with the implacable grinding mill of natural selection. Turned out, though, that natural selection couldn't generate complexifying variation as efficiently as Lamarck's "subtle fluid," whatever that really was.
Unfortunately for us today, Erasmus Darwin's fame died with the 19th century and Lamarck is notorious for his obscurity. Fortunately Samuel Butler in "Life and Habit" came up with a more accessible summary of their views that we can use as our jumping off point.
Butler opted for Erasmus Darwin's "living filament "over Lamarck's "subtle fluid," fortuitously pointing forward to the genome. We may therefore begin a Post Positivist theory of evolution by supposing the genome to be Lamarck's complexifying agent, magically generating new capabilities with potential for new uses while not presumably being the drag on development that mere mutation of genes is likely to be.
We must then ask of the genome two talents. One is intelligently-applied trial and error, demanding of the genome some degree of intelligence. The other is an ability to read success in the application of that intelligence into corresponding properties in genes. No problem. As I have suggested elsewhere, if the genes act as the genome's brain then just by wishing it so the genome could think the necessary changes into the appropriate genes. We see a similar command of brain activation by an intelligence when a dancer effortlessly translates a concept of movement into a massive program of brain cell firings resulting in precisely coordinated contractions of hundreds of muscles.
Hey Presto, a new theory of evolution. Now our work begins. What can we do with such a theory? How can we use it to enrich our experience of the world and of ourselves? That's a task worthy of the humanities.
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Life and Habit, published 1877. Online.
Butler illustrates for us how significantly non-scientists can contribute to evolutionary theory. ln 1859 when Darwin's "Origin" shattered the last remnant of his Christian faith Butler abandoned training for the clergy. He became first a sheep farmer in New Zealand, then a "Bohemian" painter and writer in London. After starting as a committed Darwinist he came to despise Darwin for failing to credit his grandfather for his evolutionary theories. To Darwin's "Descent of Man" in 1871 he responded in 1877 with "Life and Habit" in which he tried to apply Lamarckism to human evolution.
The book disappointingly trails off without arriving at any alternative theory of human evolution. But along the way Butler has developed several key concepts. He begins by showing how Lamarckism can account for the origin of variation: he illustrates conscious thought leading by degrees to habits, how these can lead to inherited instincts, and these finally can become embodied in new living tissues with new functions. He can't identify the mechanism for Lamarckism but he can make plausible that it happens.
Unlike Darwin though, he's not content for evolution to be defined in terms of behaviors and body parts. What else gets passed down through the generations, Butler asks, and begins a meditation on the meaning of evolution. What's it for? Take chickens--which is more important, the chicken or the egg? What is a chicken but an egg's way of making another egg? Maybe the whole point of chickens is to make possible the evolutionary development of eggs. And having called into question our unconscious identification of the individual adult as the product of evolution he makes the point that personality also is inherited. He ends by picturing our evolution as a the slow development, over aeons, since the dawn of evolution, of personality. Our adult bodies and our repertoire of instincts and behaviors can be seen as merely supports for the slow evolution of personality.
Butler doesn't make the point specifically, but along with personality could go consciousness and volition.
Where is the driver for this process? Butler emphatically plumps for Erasmus Darwin's "living filament" as his term for the agent of evolution, a remarkable fore-fingering of the genome.
That is as far as Butler can go. But it's not a stretch to read into Butler's speculations the idea that the conscious volition each of thinks of as our personal pride and joy is nothing more than a cross section of the genome's own progress in evolving the capacity for conscious volition, for a purpose we may never know.