Darwin's doctrine of the origin of species, which appeared in the 19th century in scientific and pseudo-scientific circulation, literally blew up European thought. There were many opponents of this theory, but also many of its most ardent adherents. The concept that living organisms adapt to changing conditions and survive as a group, only those who have managed to adapt has formed the basis of numerous social theories. The idea of species has been extrapolated to human individuals, social strata, and even entire nations and races.
Philosophical positivism, which was inclined to consider the development of the world and society as progressive progress, turned out to be the most susceptible to the teachings of a brilliant biologist. It was among the positivists (A. Small, T. Malthus, G. Spencer and others) that a theory was born, which later received the name "Social Darwinism". Scientists of this school simply "overturned" the doctrine of evolution and natural selection, which reigns in the wild, on human society. So, the British philosopher Herbert Spencer argued that the fittest people survive. And with this phrase, the famous positivist, unfortunately, demonstrated his ignorance in the basics of biology and misunderstanding until the end of Darwin's teachings, of which he considered himself a follower.
The theory of Charles Darwin claims that the fittest and most powerful individual transfers its strengths to descendants. It does not at all follow that a weak specimen will die, starve to death, be pecked or torn away by its relatives. Simply, the male most adapted to the created natural conditions will be the preferred partner in the eyes of females who wish to transmit this genotype to their offspring. The transmission of a stronger genotype is the driving factor for the change of the whole species, and not some part of it. The whole species may turn out to be unsuitable for new natural circumstances (we call it a dead end branch in evolution), or it may be that its representatives will begin to change and develop.
However, social Darwinism considers natural selection as a struggle for existence within a species, between individuals. Being rich, taking possession of natural resources and having political power is far from the same thing as transferring your genome to as many descendants as possible. The billionaire may not have children at all, or his descendants will not have the same predatory "grasping reflex" at all as his father. In any case, such a strong individual will not change the look.
Social-Darwinism in its reflections does not at all consider the species Homo sapiens as such. He is inclined to see in human society many disparate individuals who tend to kill each other for a piece of bread. So, one of the theorists of the social theory of evolution T. Malthus argued that the population of the planet, even using an intensive method of production, increases its livelihood in arithmetic progression, while it itself multiplies in geometric progression. From such overpopulation and, as a result, lack of resources for everyone, epidemics spread and bloody wars are played out, which, in principle, is not bad, since the strongest survive in battles and epidemics.
Social Darwinism, multiplied by the racial theory of the superiority of the Aryan nation, gave rise to such an ugly phenomenon as the ideology of National Socialism. The idea that certain peoples, races or social groups are weak, and therefore must be either subordinate or even destroyed (remember that the Nazis sent their weak-minded people into the gas chambers, considering them to spoil the high rank of Aryan), still live in the minds of some ideologists. So, in the late 80s of the 20th century, a prominent Soviet scientist N. Amosov with all academic seriousness proposed a large-scale study of Soviet citizens from different social groups in order to differentiate them into two types: “weak” and “strong”. J. Sorel called the theory of social Darwinism "a social myth" that undermines the notion of social justice.