Biography |Charles Darwin - Biologist and naturalist |Futura Health

Charles Robert Darwin was born in 1809 and died in 1882. The most famous of English naturalists, author of the theory of descendants modified by means of natural selection (more commonly designated under the terms of "theory of evolution"), to which the whole of modern transformist thought was rallied, was born in Shrewsbury (Shropshire) in an affluent family, fifth child of Robert Waring Darwin, known doctor, and Susannah Wedgwood, daughter of Josiah Wedgwood, renowned ceramist andIndustry boss.

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His grandfather, Erasmus Darwin, doctor, naturalist and poet, was the author of an original work (including the famous Zomonomia), too often reduced to his unusual aspects, where the fairly exposed transformist ideas were exposed for the first timeNeighboring those that French Lamarck was going to support with great courage and quite little success from the year 1800. After painful studies of medicine in Edinburgh, then theology in Cambridge where he indulged in his passion for insectsAnd becomes the disciple and the friend of botanist John Stevens Henslow, who introduced him into the world, the young Charles was received Bachelor of Arts in 1831, and left to explore the north of Wales in the company of the geologist Adam Sedgwick, alsoProfessor in Cambridge.

Upon his return, thanks to the protection of Henslow, he embarked on a trip around the world, on December 27, as a naturalist who is not supposed, aboard the vessel Le Beagle, commanded by the young Captain Fitzroy. He wins with him a naturalist library comprising the first volume of the principles of geology of the uniformist geologist (that is to say supporter of the overall uniformity of the causes of the physical transformations of the globe, in the past as in the present) Charles Lyell . He thus explores the CAP-Vert archipelago (where he verifies the merits of Lyell theories applied to the observation of the volcanic islands), the coasts of South America (where his paleontological research leads him to put in More and more clearly evidence the resemblance between fossil and living representatives of certain types of mammals), the land of fire, the Falkland Islands, the Chiloé Island, the Andes Cordillera, the Galápagos Islands (where it has precise intuition Processes which lead to the geographic distribution of organisms and examine certain modalities of what will soon appear to him as the birth of new species from stem forms), Tahiti (where he observes a coral reef and reflects on the process of his training), New Zealand, Australia, Tasmania, Mauritius, Cape Town. In Brazil, he experienced a feeling of violent revolt in front of the slavery of blacks, which he will never cease to denounce as a unworthy defilement of certain "civilized" nations. He reports from this trip which lasted almost five years (until October 2, 1836) a Journal of Researches which contains most of the observations and materials specific to the development of his future theory. Its publication in 1839 was accompanied, over a longer period, that of the geological, paleontological and zoological documents entrusted by Darwin to the expertise of various specialists (Richard Owen for fossil mammals, George Robert Waterhouse for mammals, John Gould For birds, Leonard Jenyns for fish, Thomas Bell for reptiles) or reserved for different monographs which he will execute himself.

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As early as 1837, the progress of the investigation on travel results (that of Gould in particular) accelerated the implementation of Darwin's ideas. In July, he opened his first notebook (notebook) on the transmutation of species. In September 1838, reading the test on the principle of the population of Thomas Robert Malthus (1798) fixed its ideas by providing them with a mathematical modeling element (the tension ratio between the geometric growth of the population and the simply arithmetic increase Resources, involving competition and elimination), and leads him to give form to what will constitute the central element of his theory (natural selection resulting from the struggle for existence). In 1839, Darwin becomes a member of the Royal Society From London, marries his cousin Emma Wedgwood (with which he will settle three years later in Down, southeast of London), and undertakes an investigation by questionnaire on farming. In 1842, he published his work on Corail reefs, The Structure and Distribution of Coral Reefs, and finished the first handwritten draft of the presentation of his theory of species transformation. At the same time, he worked on a work on the volcanic islands, of which he continued the writing the following year, and which in 1844 formed the second volume of the geology of travel, of uniformitarian orientation. During this same year, he completed an essay on the common ancestry of species and their progressive training by selected modifications (second draft, which will not be published until 1909 by Francis Darwin under the title The Foundations of the Origin of Species ), that he recommends to his friend the botanist John Dalton Hooker, fearing that his bad health would prevent him from going further. His work on the geology of South America appeared in 1846. He then undertook the drafting of a monograph on the Crustaceans Cirripèdes, which will occupy it until its publication (1851-1854, 2 vol.). In 1855 and 1856, he focused on the geographic distribution of organizations, at the same time as a younger naturalist, Alfred Russel Wallace (1823-1913), whose ideas are increasingly converging with his. Concerned about the risk of seeing his friend stripped of the fatherhood of his discovery, Lyell intervenes to convince Darwin to publish his theory. Darwin then undertook the realization of a huge work which will become, after relief, the origin of the species. Having received a manuscript from Wallace where the idea of ​​a transformation of species is developed by the game of natural selection, Darwin, aware of his real anteriority and stimulated by the friendship of Lyell, Huxley and Hooker, accepts that Lyell Organize in front of the Linnean Society of London a common communication with Wallace, then in Malaysia ("On the Tendency of Species to Forma varieties, and on the perpetuation of varieties by natural means of selection"), which takes place on July 1, 1858. Darwin Then summarizes his manuscript and finally publishes it under the title on the Origin of Species by Means of Natural Selection, or the Presenation of Favoured Races in the Struggle for Life, November 24, 1859. The first edition was exhausted as soon as possible. Cautiously, Darwin introduces in the second (1860) the express mention of the Creator, but his thought has already detached without return from religious conformism and natural theology that have reigned over his years of learning. The providentialist idea is dismissed forever, in favor of a natural explanation of the balances and dynamics that govern the future of the living world.

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From the following year (1861), he began a work on the variation of organizations. In 1862, he published a book on the fertilization of orchids, then, in 1863, worked on floral dimorphism, on mimicry, again on the fertilization of orchids, on spontaneous generation and natural selection, without abandoning geology. In 1864, he wrote a study on climbing plants which was published the following year, and obtained the COPLEY medal of the Royal Society of London. In 1868, he published The Variation of Animals and Plants Under Domestication, a vast illustration of the theses of origin which contains in his latest chapter a "provisional hypothesis" on the generation quite significantly inspired by the Newtonian tradition (Buffon, Maupertuis), the Theory of the "pangnesis", and begins to work at The Descent of Man, and Selection in Relation to Sex, a major work which will appear in 1871. In 1872 appear the 6th edition (regarded as final) of The Origin, and The Expression of The Emotions in Man and Animals, which will play a role in the theoretical inspiration of modern psychology and ethology. In 1875 appeared insectivorous plants and the volume publishing of work on climbing plants, on the movement and clothes of climbing plants. In 1876, the effects of cross and self fertilization in the vegeatable kingdom. In 1877, The Different Forms of Flowers on Plants of the Same Species. In 1880, The Power of Movement in Plants. In 1881, The Formation of Vegetable Mould, through the Action of Worms. On April 19, 1882, Darwin died in Down, leaving an immense correspondence, unpublished notes and an autobiography written in 1876 for his children, that the concern for respectability of Emma Darwin - with regard to the convictions expressed in matter of religion and judgments made on still alive people - will ampute for a time of some of its most interesting passages. Darwin's body, accompanied by eminent personalities, will be buried a week later, after an imposing ceremonial, in the "English pantheon" of Westminster Abbey.

The permanent news of Darwinian thought (always in debate inside and outside its strictly naturalistic field of application) is the exceptional sign of consistency and strength of its issues. If the periodic and multifaceted resurgence of creationism (biblical theory, more or less adapted according to the circumstances and the currents, of the separate creation of the species by an omniscient personal god), despite the recent readjustments of the Catholic Church recognizing the fact of The evolution while still trying to rule out its legitimate theoretical consequences, repeats the structure of the first opposite resistances and objections (by fixist creationists or certain finalist "evolutionists) to the Darwinian transformism, other strategies (like Creation Those implemented by American sociobiology in its most brutal applications to the life of human societies), on the contrary, aim to draw from a radical, exclusive and summary reference to the founding concepts of selective theory of illegitimate consequences and contrary to logic expressly developed by Darwin over his biological and anthropological reflection. These perpetually reborn debates most often rest on a land ignorance of texts and rationality specific to Darwinian theory seized in all of its dimensions.

The origin of the species (1859) and the theory of descendants modified by the means of natural selection.

A logical diagram in ten points sums up the didactic presentation of the Darwinian thesis:

1. All living beings, whether they live in their natural state or in domestic condition, have individual organic variations, more frequent and easily observable in the second case.

2. induces the existence of an indefinite natural capacity for variation in organisms (variability).

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3. We observe that an oriented reproduction can fix hereditaryly some of these variations (advantageous for humans) by accumulation in a determined sense, with or without reasoned or methodical project (artificial selection, unconscious selection).

4. We induces the hypothesis of an ability of organisms to be selected in a similar manner within nature ("selection").Question: What can be the “natural selection” agent thus inferred from this proven “selection” (by its domestic updates) of organic variations?

5. We assess the reproduction rate of various species and their population of settlement.

6. We deduce the existence of a natural capacity for total and rapid occupation of any territory by representatives of a single species, animal or plant, reproducing without obstacle.

7. However, we observe almost universally, instead of this saturation, the existence of natural balances constituted by coexistence, on the same territory, representatives of multiple species.

8. We deduce from the opposition between points 6 and 7 the need for a regulator mechanism operating within nature and reducing the digital extension of each population.Such a mechanism is necessarily eliminatory, and is opposed by destruction to the natural trend of each group of organisms with unlimited proliferation.It is the struggle for existence ("Struggle for Life"), which makes a natural selection whose main effect is the survival of the most capable (by the play of elimination less capable).Question: What determines better adaptation?

9. We observe the struggle for existence within nature.

10. To answer the question of the factors of better adaptation, we return to variability, and, under the analog pressure of the model of artificial selection, we forge the hypothesis of a natural selection which, through thestruggle (interindividual, interspecific and with the environment), would sort out advantageous variations in a given context, and thus ensure the vital triumph, hereditary transmissible, of the individuals who would carry it.The latter would thereby be on the way to a constant improvement of their adaptation to their living conditions and those of the struggle: "It is to this conservation of favorable variations", writes Darwin, "and the destruction ofThose that are harmful, which I applied the name of 'natural selection' or 'survival of the most capable'.(The origin of the species, ch. IV.)

These are the main logical moments, since the empirical fact observed and oriented of the variation of organisms (essentially individual phenomenon) until the formulation of the theory of natural selection (which extends the workforce of organisms carrying the advantageous variation) , Darwin's transforming reflection. This dynamic of the progressive transformation of living species by means of accumulation, in a sense determined by the adaptive advantage, of light variations (gradualism), leads to reject the theological idea of ​​the independent creation of species immutable by a Personal creator and omni-prevoyant. The species descend one of the other according to a continuous process of divergence, by means of modifications occurring "at random" (which only means for Darwin that we still do not know its determinism), and which are selected and transmitted. A large number of ancestral species have turned off during the immense duration of geological times, which explains the absence of certain "intermediate forms" between the currently distinct and known species, and between the latter and the fossil species. We are often mistaken by demanding to discover directly intermediate forms between known species, while research must relate to the intermediate forms between these forms and a common and unknown ancestor. The paleontological archive, although delivering precious testimonies in support of genealogical theory, proves to be insufficient in this regard, due to its limited exploration and the physical erasure of the traces of certain categories of beings; But the study of the geographic distribution of organisms, that of rudimentary bodies, examination of embryogenetic development and the analysis of classification devices themselves, as well as the attention paid to crossings and hybridizations, make it possible to reconstruct the stages probable of the evolution of living beings, accrediting the idea that varieties are emerging species and that all living beings can have a common origin. Thus, from the selected variations of organizations, but also instincts, the final prediction of Darwin: “Our classifications, as far as they can go up, will come to be genealogies. ... Psychology will be established on a new basis, that of the necessary and gradual acquisition of each mental faculty. The light will be made on the origin of man and his history. »»»»

Man's parentage (1871) and Darwin's anthropology

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The Descent of Man and Selection in Relation to Sex, third major synthesis of Darwin after The Origin and The Variation, was introduced in France through the translation of Jean-Jacques Moulinié (1872), where Descent (which means the fact To "descend from", to be from a strain or a line, to come from an origin, to proceed from a series of ancestors, to represent the current culmination of a genealogy, In short, to have an ancestry) is rendered by "descendants", whose use in French, in such a job, is rare and disputed. Precise semantic reasons made us prefer for this translation the term "filiation" taken in its legal meaning - establish the parentage of someone consisting in authenticating their ancestry by going up along the link (descendants) which unites until him individuals directly from each other by an act of generation. The use having however largely imposed, in this case, of the term "descendants", we can occasionally maintain it, taking into account this development.

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If we measure in all its magnitude the shock produced in the consciences by the origin of the species, already widely disseminated at this time in the United States and on the European continent, we can assess the interest that could arouse in 1871 aWork expected and presented as the extension to man of the theory of descendants with modifications, and therefore as the definitive emancipation of naturalistic discourse in relation to the most resistant of theological prohibitions, that which tended to ultimately preserve the man ofHis registration in the animal series.The scientific stake of such a book then appeared to be inseparable from determining philosophical and political issues at the heart of an era of expansion and consolidation of colonial rights of way, and in a restructuring society which was the theater of a conflictNot only between conservatism and liberalism, but also between different versions of conquering liberalism.

A. Darwinian transformism extended to man

""

“L'unique objet de cet ouvrage

»», écrit Darwin, ""

“est de considérer : premièrement, si l'Homme, comme toute autre espèce, descend de quelque forme préexistante; secondement, le mode de son développement; et, troisièmement, la valeur des différences existant entre ce qu'on appelle les races humaines .

»»

Le premier temps de la démonstration de Darwin consiste à établir la liste des phénomènes de ressemblance qui selon lui rendent indiscutable le lien qu'il veut établir entre la constitution anatomo-physiologique de l'Homme et celle des autres membres du groupe des Vertébrés. Ses arguments, empruntés d'abord à l'anatomie comparée, et particulièrement à Huxley, sont déjà classiques : identité de conformation du squelette, des muscles, des nerfs, des vaisseaux, des viscères, et même de l'encéphale lorsqu'il s'agit des Singes supérieurs; communicabilité réciproque de certaines maladies entre les animaux - les Singes surtout - et l'Homme; parenté entre les parasites qui affectent les Hommes et les animaux; analogie également entre les processus qui, chez les uns et les autres, suivent les phases de la lune, entre les phénomènes cicatriciels, entre les comportements reproducteurs, entre les différences qui séparent les générations et les sexes, entre les stades et les mécanismes du développement embryonnaire, singulièrement lorsque l'on observe la parturition des Singes; communauté de la détention d'organes rudimentaires; existence d'un revêtement laineux (lanugo) chez le fœtus humain au sixième mois; traces persistantes, chez l'Homme, à l'extrémité inférieure de l'humérus, du foramen supra-condyloïde, ouverture par laquelle passe, chez ""

“quelques Quadrumanes, les Lémurides et surtout les Carnivores aussi bien que beaucoup de Marsupiaux »», le "" grand nerf de l'avant-bras et souvent son artère principale

»", etc.

Mais les données mises en œuvre par la grande somme compilatoire et illustrative que constitue The Descent excèdent considérablement les seuls domaines de l'anatomie et de la physiologie comparées. Celles que Darwin emprunte également à l'anthropologie physique, à l'anthropométrie, à l'éthologie humaine et à l'étude des sociétés "" civilisées »» et des cultures exotiques (dont certaines remontent à sa propre expérience de voyageur) lui fournissent les éléments qui lui permettent de mettre en évidence le fait que la variabilité, prouvée chez l'Homme sur le terrain de l'anatomie, l'est également sur les plans raciologique et sociologique, et que, sous des modalités qui n'ont été, hélas, convenablement analysées que bien tard, la sélection se poursuit au sein de l'humanité.

B. The reversive effect of evolution

Darwin therefore engages in parentage to an essay - inevitable from the point of view of the coherence and the scope of his theory - of unification of all biological and human phenomena under the operation of a single principle ofExplanation of becoming: the latter very normally derives from the natural sciences which have just been listed, Darwin traveling their different fields to lead smoothly in the field of what we would call social anthropology today, as well as toPsychosociological and ethical observations which, to be specifically human, are nonetheless evolved to data and behaviors whose analysis tends to reveal the origin within animal groups.

Or, contrairement aux interprétations qui ont dominé pendant plus d'un siècle la lecture (en réalité, dans la plupart des cas, la non-lecture) du texte de La Filiation, ce continuisme ne fonde ni ce que l'on a appelé d'une manière expéditive le "" darwinisme social »», présent au contraire chez Spencer et Haeckel, ni, sous le motif de la "" poursuite de la sélection »», aucune forme ultérieure d'inégalitarisme social ou racial. En effet, La Filiation établit qu'un renversement s'est opéré, chez l'Homme, à mesure que s'avançait le processus civilisationnel. La marche conjointe du progrès (sélectionné) de la rationalité, et du développement (également sélectionné) des instincts sociaux, l'accroissement corrélatif du sentiment de sympathie, l'essor des sentiments moraux en général et de l'ensemble des conduites et des institutions qui caractérisent la vie individuelle et l'organisation communautaire dans une nation civilisée permettent à Darwin de constater que la sélection naturelle n'est plus, à ce stade de l'évolution, la force principale qui gouverne le devenir des groupes humains, mais qu'elle a laissé place dans ce rôle à l'éducation. Or cette dernière dote les individus et la nation de principes et de comportements qui s'opposent, précisément, aux effets anciennement éliminatoires de la sélection naturelle, et qui orientent à l'inverse une partie de l'activité sociale vers la protection et la sauvegarde des faibles de corps et d'esprit, aussi bien que vers l'assistance aux déshérités. La sélection naturelle a ainsi sélectionné les instincts sociaux, qui à leur tour ont développé des comportements et favorisé des dispositions éthiques ainsi que des dispositifs institutionnels et légaux anti-sélectifs et anti-éliminatoires. Ce faisant, la sélection naturelle a travaillé à son propre déclin (sous la forme éliminatoire qu'elle revêtait dans la sphère infra-civilisationnelle), en suivant le modèle même de l'évolution sélective - le dépérissement de l'ancienne forme et le développement substitué d'une forme nouvelle : en l'occurrence, une compétition dont les fins sont de plus en plus la moralité, l'altruisme et les valeurs de l'intelligence et de l'éducation. Sans rupture, Darwin, à travers cette dialectique évolutive qui passe par un renversement progressif que nous avons nommé l'effet réversif de l'évolution, installe toutefois dans le devenir, entre biologie et civilisation, un effet de rupture qui interdit que l'on puisse rendre son anthropologie responsable d'une quelconque dérive en direction des désastreuses "" sociologies biologiques »». Il s'oppose ainsi expressément au racisme, au malthusianisme et à l'eugénisme, contrairement à l'erreur courante qui lui attribue la justification de ces trois systèmes de prescriptions éliminatoires. Cette remarquable dialectique du biologique et du social, qui se construit pour l'essentiel entre les chapitres III, IV, V et XXI de La Filiation et qui, en plus de s'opposer à toutes les conduites oppressives, préserve l'indépendance des sciences sociales en même temps qu'elle autorise et même requiert le matérialisme éthique déductible d'une généalogie scientifique de la morale, n'a été reconnue dans toute sa force logique qu'à partir du début des années 1980. Le continuum biologico-social darwinien, dont une bonne métaphore didactique est l'image topologique de la torsion du ruban de Möbius, est un continuum réversif, impliquant donc un passage progressif au revers de la loi évolutive initiale - la sélection naturelle, en tant que mécanisme en évolution, se soumettant elle-même, de ce fait, à sa propre loi. Il faudra sans doute revenir longtemps sur l'explication de ce concept qui rend caduque la prétention ordinaire de la plupart des philosophies à déclarer inconcevable la possibilité même d'un matérialisme intégral englobant l'éthique.

C. Sexual selection

The treatment of sexual selection in parentage is extremely documented, and travels a very large zoological domain before returning to man after a long detour passing through the question of the digital proportion of the sexes (sex-ratio) and differencesbetween sexes in animal species.

La sélection sexuelle dépend "" de l'avantage que certains individus ont sur d'autres de même sexe et de même espèce, sous le rapport exclusif de la reproduction »» (ch. VIII). En d'autres termes, la sélection sexuelle ne repose pas directement sur la lutte pour l'existence, mais essentiellement sur une rivalité des mâles dans la compétition pour la possession des femelles, compétition dont les effets, moins rigoureux en règle générale que ceux de la sélection naturelle, sont momentanément disqualifiants pour les vaincus ou les évincés, sans être en principe définitivement éliminatoires. La sélection sexuelle, qui sélectionne des caractères sexuels secondaires et repose en grande partie sur l'hérédité "" liée à un seul sexe »», assure généralement le triomphe des mâles les plus vigoureux et les plus combatifs, ou de ceux qui possèdent une particularité morphologique favorisant leur suprématie au sein de cette compétition (cornes et ergots plus développés respectivement chez le Cerf et le Coq, crinière plus épaisse chez le Lion, plumage plus éclatant et chant plus mélodieux chez les Oiseaux). La préférence et le choix exercés par les femelles jouent dans ce processus un rôle déterminant. Darwin retrouve au sein de l'espèce humaine des traits de comportement qui manifestent la persistance d'une sélection sexuelle sous les critères (variables suivant les cultures) de la beauté masculine et féminine, et reconnaît le rôle qu'ils jouent lors des choix nuptiaux. La sélection sexuelle, complément de la sélection naturelle, peut cependant avoir des effets anti-adaptatifs : par exemple la lourde parure de noce de tel Oiseau mâle pendant la période des parades nuptiales peut l'empêcher quasiment de voler et constituer ainsi un obstacle à sa survie. Que la tension vers l'union sexuelle reproductive - qui possède à l'évidence un lien d'origine avec ce que l'on appelle l'amour - puisse comporter d'une manière intime et permanente un risque de mort est une observation darwinienne qui ne devrait pas échapper à la perspicacité de la psychanalyse.

D. Sexual selection and natural selection

Sexual selection, as we have said, selects secondary sexual characteristics, that is to say organs or morpho-anatomical features belonging to a single sex (male sex in this case), which,Without having a direct link with generation, however, promote its accomplishment: this is the case, for example, of the grip organs developed in males only many species (certain crustaceans in particular), and which are used to grasp and maintainThe female during mating.

Heredity linked to a single sex is therefore necessary to think about the transmission of secondary sexual characteristics. When the latter are the occasion for superiority in the struggle, the individuals who are carrying it, and who are therefore capable of generating a greater number of descendants and ensuring its protection, transmit to these this advantage. Admittedly, natural selection is enough to explain in the male the existence of organs such as the organs of the senses and the locomotion, which are used to find the female, at the same time as to many other uses which seem specially intended for Holding the female during mating. However, sexual selection had to play a significant role in the formation and improvement of these organs, insofar as it is this very improvement which ensures certain males their domination over other males, and confers on the best armed The ability to transmit this advantage to their male descendants. It should also be noted that the advantaged males having the possibility of conquering the healthiest and most vigorous females, which are also the earliest in terms of the ability to generate, the advantage is distributed among the descendants of the two sexes in the common form of increased health and physical vigor.

""

“La sélection sexuelle »», écrit Darwin, "" a dû provoquer le développement de beaucoup d'autres conformations et de beaucoup d'autres instincts; nous pourrions citer, par exemple, les armes offensives et défensives que possèdent les mâles pour combattre et pour repousser leurs rivaux; le courage et l'esprit belliqueux dont ils font preuve; les ornements de tous genres qu'ils aiment à étaler; les organes qui leur permettent de produire de la musique vocale ou instrumentale et les glandes qui répandent des odeurs plus ou moins suaves; en effet, toutes ces conformations servent seulement, pour la plupart, à attirer ou à captiver la femelle. Il est bien évident qu'il faut attribuer ces caractères à la sélection sexuelle et non à la sélection ordinaire, car des mâles désarmés, sans ornements, dépourvus d'attraits, n'en réussiraient pas moins dans la lutte pour l'existence, et seraient aptes à engendrer une nombreuse postérité, s'ils ne se trouvaient en présence de mâles mieux doués. Le fait que les femelles, dépourvues de moyens de défense et d'ornements, n'en survivent pas moins et reproduisent l'espèce, nous autorise à conclure que cette assertion est fondée.

»(Ch. VIII.)

Thus, sexual selection is superimposed on natural selection, also working on an improvement which, to be of the order of reproductive aptitude and the male online transmission of advantageous secondary characteristics, nevertheless reachesBeneficially all of the conformation and land health of individuals of both sexes, by the double movement that pushes the males best gifted to seize the healthiest females and the sooner ready for fertilization, and the femalesTo prefer the most attractive males, which results in a global improvement in the physical level of descendants: it therefore becomes difficult to disentangle what is due to sexual selection and what is the ordinary effect of natural selection.

It is interesting to note that the reasoning which in Darwin serves to establish the naturalness of sexual selection is the same which served to establish that of natural selection: as well as man practices an artificial sexual selection on his animals Domestic - improving in the sense of its tastes or needs such or such breed of rooster for example -, likewise, that nature has the capacity to select secondary sexual characteristics (whose variability is clearly accused), in The meaning of a reproductive advantage, and thus to improve the physical aspect of males of such or such species. Darwin's explanatory approach with regard to sexual selection in man parentage is indeed exactly parallel to that which was implemented in 1859 in the origin of species to make people understand, through the proven existence of Artificial selection, the likely existence of a selection operating freely within nature:

""

“De même que l'homme peut améliorer la race de ses coqs de combat par la sélection de ceux de ces oiseaux qui sont victorieux dans l'arène, de même les mâles les plus forts et les plus vigoureux, ou les mieux armés, ont prévalu à l'état de nature, ce qui a eu pour résultat l'amélioration de la race naturelle ou de l'espèce. Un faible degré de variabilité, s'il en résulte un avantage, si léger qu'il soit, dans des combats meurtriers souvent répétés, suffit à l'œuvre de la sélection sexuelle; or, il est certain que les caractères sexuels secondaires sont éminemment variables. De même que l'homme en se plaçant au point de vue exclusif qu'il se fait de la beauté, parvient à embellir ses coqs de basse-cour, ou pour parler plus strictement, arrive à modifier la beauté acquise par l'espèce parente, parvient à donner au Bantam Sebright, par exemple, un plumage nouveau et élégant, un port relevé tout particulier, de même, il semble que, à l'état de nature, les oiseaux femelles, en choisissant toujours les mâles les plus attrayants, ont développé la beauté ou les autres qualités de ces derniers.

»(Ch. VIII.)

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Il semble donc d'une manière générale que chez presque tous les animaux à sexes séparés, il doive y avoir une compétition "" périodique et constante »» entre les mâles pour la possession des femelles, compétition au sein de laquelle la force, les armes et la beauté physiques des mâles d'une part, le choix exercé par les femelles d'autre part, jouent un rôle déterminant.

Au terme d'un long recensement, Darwin aboutit à la conclusion suivant laquelle les caractères sexuels secondaires sont généralement plus accentués chez les mâles des espèces polygames. En voici la raison : on admet au départ qu'une prépondérance numérique des mâles sur les femelles constitue une condition favorable à la rivalité des mâles, donc au développement chez ces derniers de caractères sexuels secondaires plus ou moins marqués selon les individus, d'où il suit que les mieux armés l'emporteront dans la compétition reproductive. Or la polygamie, qui est la situation où un seul mâle, en raison de sa force, de sa combativité ou de sa séduction, gouverne un harem de femelles, produit les mêmes effets que l'inégalité numérique des sexes : de nombreux mâles - ""

“et ce sont certainement »», écrit Darwin, "" les plus faibles et les moins attrayants

»(Ch. VIII) -, will not be able to mate.We can also think that given this situation, it will be all the more qualities to a male not only to conquer, but to keep his females and protect his young.The males excluded from coupling are not generally in a permanent way, but most of the time can unite with less lively females, which reflects negatively on the quality of their descendants of the two sexes.

Changes that determine the intersex differences in external appearance in many species are generally more accused in male than in the female.The fact that males are more ardent, more combative, and that they almost always have the initiative of the romantic pursuit, indirectly leads to a more frequently remarkable development of secondary sexual characteristics in the male.However, it should be remembered that the apparent passivity of the females does not exclude, however, from their part a certain choice in the acceptance of the male.

A final idea must be mentioned here, in response to a current error which wanted to make Darwin the theorist of the natural inferiority of women.Certainly, Darwin analyzes in evolutionary, then historical terms, the reasons for the statutory inferiority of women in the society that is contemporary to it.But he sees in education the spring of their upcoming equality, and the conviction he defends from a detention by women of this original and germinal form of the social instinct (base of moral feelings) that'maternal love leads him logically to place in them the hope of the future emotional and ethical evolution of humanity.

The alterations of Darwinism in Victorian times

La persistance extraordinairement tenace d'erreurs d'interprétation concernant le versant anthropologique de la pensée darwinienne s'enracine dans le moment précis qui sépare la publication en 1859 de L'Origine des espèces et celle, en 1871, de La Filiation de l'Homme. Cette décennie décisive, au cours de laquelle les partisans de Darwin - lesquels étaient pour la plupart loin d'être "" darwiniens »» - incitèrent sans relâche ce dernier à étendre à l'Homme son propos transformiste dans un livre qui, pour avoir été trop longtemps attendu, ne sera pratiquement jamais lu dans sa littéralité ni entendu dans sa logique, a vu en effet se développer le "" système de l'évolution »» du philosophe Herbert Spencer et son "" darwinisme social »», application impitoyable du principe de l'élimination des moins aptes au sein d'une concurrence sociale généralisée. Elle a vu également, à partir de 1865, la naissance de l'eugénisme de Francis Galton, recommandant l'application compensatoire d'une sélection artificielle aux membres du groupe social pour lutter contre la dégénérescence issue de l'affaiblissement du rôle de la sélection naturelle en milieu de civilisation. Ces discours - parfois inconciliables dans leurs principes mais convergents dans leurs effets - développaient ensemble une référence également réductrice à la théorie darwinienne de la sélection, dans un accord global avec les tendances dominantes de la société industrielle anglaise emportée par l'ivresse de sa métamorphose libérale. Aucune de ces deux "" déviations »» n'a reçu l'aval de Darwin, qui a pris position dans l'ouvrage de 1871 contre les positions et recommandations sociales et politiques qui en émanaient. Mais la confusion était née, soutenue par un système de pensée et ancrée dans le vocabulaire théorique, de sorte qu'aujourd'hui encore, un travail idéologique incessant s'obstine, contre l'évidence historique, logique et textuelle qui ressort de l'examen approfondi de l'œuvre darwinienne, à parer du nom et du prestige de Darwin - le plus souvent au moyen de montages citationnels - des doctrines ou des pratiques, telles que l'anti-interventionnisme social radical, l'impérialisme, le racisme, le "" sexisme »» ou l'eugénique négative, qu'il a toujours expressément combattues.

Books :

- C. DARWIN, 1809-1882, The Autobiography, edited by Nora Barlow, New York, Londres, Norton & C°, 1993 ;

- C. DARWIN, L'Origine des espèces au moyen de la sélection naturelle ou la lutte pour l'existence dans la nature, trad. J.-J. Moulinié (d'après les 5e et 6e éditions anglaises), Verviers, Gérard & C°, Marabout-Université, 1973 ;

- C. Darwin, Man's parentage and selection linked to sex, Paris, Syllepse, 1999;P. Tort,

- Hierarchical thought and evolution, Paris, Aubier, 1983;P. Tort (dir.),

- Darwinism and society, Paris, PUF, 1992;P. Tort (dir.),

- Dictionary of Darwinism and Evolution, Paris, PUF, 1996, 3 vol.;P. Tort,

- Spencer et l'évolutionnisme philosophique, Paris, PUF, "" Que sais-je ? »» n° 3214, 1996 (épuisé) ; P. TORT (dir.),

- For Darwin, Paris, PUF, 1997;P. Tort,

- Darwin et la science de l'évolution, Paris, Gallimard "" Découvertes »», 2000 ; P. TORT,

- The second Darwinian revolution, Paris, Kimé, 2002.

- P. Tort, Darwin and philosophy, Kimé.