La filiation de l'homme et la sélection liée au sexe

Charles Darwin's The Descent of Man, and Selection in Relation to Sex is the follow up to the Origin of Species. In the latter, he carefully avoided to include humankind in his theory of evolution by natural selection. This book, published 13 years after The Origin, remedies this situation. It actually comprises two very different books. The first part is focused on the demonstration that humans are actually primates, and share common ancestors with apes. A side discussion is dedicated to the demonstration that all human races are part of a unique species. A second part aims at completing the natural selection between species presented in The Origin with sexual selection within species, explaining the differences, morphological or otherwise, between the two sexes. This second part is quite encyclopedic. It shows how detailed and thorough Darwin was when it came to support his view. However, apart from an avalanche of entertaining facts about animals' sex dimorphism (Darwin never mentioned plants in this book, and barely mention them in The Origin), not much remains scientifically valid. By 1972, Darwin had become completely convinced by the transmission of acquired traits (which was absolutely mainstream at the time), and more to the point had developed his theory of pangenesis, whereby “gemules” were sent over the lifetime from all parts of the body to the germs. This notion completely falsified all his thoughts about selection, in particular in relation to age. While reading The Origin remains a must for anyone interested in evolution, with large swats of it still relevant today, The Descent only presents an historical interest.
The last chapters talk about differences between man and woman is a reflect of the times, and might be found offensive today.

Souvent mal lue, la théorie de Darwin, appliquée aux sociétés humaines sous le nom de Darwinisme social, validerait les crises capitalistes et leurs vagues d'exclusions, voire d'éliminations, comme évolution nécessaire et saine pour la société.

Ce livre est le pendant de la théorie de l'espèce, le contre point nécessaire pour voir que la Nature sélectionne par la sexualité, et que l'argent ne pourra jamais égaler la vertu de cette Nature, mais fera toujours semblant de le pouvoir, par la force militaire.