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Charles Darwin on the origin of human morality
and the problem of eugenics

A review by Gert Korthof.   26 april 2008

Descent of Man
book The Descent of Man, and selection in relation to sex.
by Charles Darwin, Princeton University Press (1981) 475 pages.
PUP edtion is a photoreproduction of the 1871 edition of J. Murray.
With an introduction by J.T. Bonner and R.M. May.
See online editions: (1). All page numbers in this review are from
the first 1871 edition, unless stated otherwise.

    The task of Descent of Man is to show that humans are descended from lower forms and have their place in the tree of life just as Darwin did for animals and plants in The Origin of Species. Furthermore, that the mechanism that produced humans is heritable variation and natural selection. In this review I focus on chapter III (Moral Sense) and chapter V (Intellectual and moral faculties of man).
Ethologists such as Frans de Waal started to investigate the biological origins of morality in the 1980s and 1990s (2). De Waal investigates morality from a Darwinian perspective. I assumed that Darwin did not write very much about the origin of human morality. I was wrong. Darwin wrote extensively about moral sentiments in The Descent of Man (3). One could even wonder what's new in the theories of today's evolutionary ethologists. Additionally, I discuss the question: Was Darwin an eugeneticist?

Chapter III. Comparison of the mental powers of man and the lower animals

What is the problem?

Immediately a problem arises. According to Darwin, the most distinguishing characteristics of the humans species are the intellectual and moral capacities. How then could humans evolve from animals which do not have morality?

What are Darwin's arguments for the evolution of human morality from lower animals?

Darwin's explanation of the origin of morality starts with a definition of 'moral sense'. Darwin defines the moral sense as fundamentally identical with the social instincts (p.98) or: our moral sense is ultimately derived from social instincts (p.97). Social instincts are directed towards 'the good of others' (others within the group). (p.93)

Do animals have social instincts?

Then, Darwin observes that humans as well as animals have social instincts. He bases this on the observation that higher social animals are inclined to aid their fellows (of the same group) in general ways (4). Next, Darwin reasons that animals exhibit qualities which in us would be called moral (p.78).

Do humans have social instincts?

Humans help and have sympathy for in-group members, and kill out-group members and social instincts are still the basis of 'many of his best actions' (p.86). This gave man a rude rule of right and wrong (p.103). In humans 'Good' and 'Bad' are defined by the positive effect on the welfare of the tribe, not outside the tribe and not on the individual (p.96). In humans the 'general good' may be defined as the means by which the greatest possible number of individuals can be reared in full vigor and health (p.98) (5).

Where do social instincts come from?

Having explained moral sense by social instincts, the next question becomes: Where do social instincts themselves come from? According to Darwin, they are an extension of the parental or filial affections (p.80) and most importantly, they are naturally selected because it is beneficial for the members of the group (p.80). Just as killing out-group individuals is beneficial for the group (p.81) (very modern view!). Those groups with the greatest number of sympathetic members would flourish best and rear the greatest number of offspring (p.82) (6).

How is it possible that humans have a higher moral level than animals?

According to Darwin, the moral sense is enhanced by the power of reasoning, knowledge of the wishes of his fellow creatures, fear for disapproval or (divine) punishment (p.92). This is Darwin's explanation why human morality today is on a higher level relative to earlier periods and relative to social animals. Human morality improves further when groups become larger or united and social instincts extend to the larger group or nation. Furthermore, "his sympathies became more tender and widely diffused, so as to extend to the men of all races, to the imbecile, the maimed, and other useless members of society, and finally to the lower animals." (p.103). Darwin is optimistic in that he is confident that morality improves further and will not disappear (7). Darwin clearly sees what moral improvement could mean, but still uses the values of his society!

Conclusion of chapter III

Although the difference between the mind of the lowest man and the highest animal is immense, and the moral sense is perhaps the best and highest distinction between man and the lower animals, (p.106) the difference certainly is one of degree and not of kind (p.105).

My comments:

I think Darwin views morality, -moral behaviour- as a necessary condition for the existence of a group. It follows from: "No tribe could hold together if murder, robbery, treachery were common" (p.93) So, a form of morality exist almost by definition in animals living in groups. It is no surprise that Darwin used the principle of group selection to explain the evolution of human morality (8).
I my view, the main differences between morality in animals and man are:
  1. humans created a theoretical system of moral rules once language was developed (Ten Commandments, etc.)
  2. humans live in larger groups (societies, nations) so their social behaviour is directed to a larger group, but killing of strangers is common especially in wars (the enemy)
  3. humans think they are morally better than animals, are more altruistic, because they have developed a theoretical moral system (9) and Christians think they have a unique foundation for a moral system.
However, there is a great discrepancy between any moral theory and practice. What we need is (1) an accurate assessment of actual human behaviour. How often do humans risk their lives to save a fellow creature? or a stranger? (2) the frequency of anti-social behaviour and murder in peace and wartime. Too often evolutionary biologists are pre-occupied with mathematical models to explain altruistic behaviour in humans without knowing the actual frequency of altruistic behaviour, ignoring war, genocide, torture.

Darwin is not concerned with the religious foundation of morality. However, when morality is based on social instincts we do not need a religious foundation of morality, it seems. So, indirectly Darwin makes a religious foundation of morality superfluous.

Chapter V. On the development of the intellectual and moral faculties during primeval and civilised times

In this chapter Darwin discusses a difficulty for the origin and maintenance of within-group altruism, which today is still of the highest importance.
"But it may be asked, how within the limits of the same tribe did a large number of members first become endowed with these social and moral qualities? ... He who was ready to sacrifice his life, ... would often leave no offpsring to inherit his noble nature." (p.163).
The first step would be that the one who aided his fellow-men would receive aid in return (today: reciprocal altruism). The second step would be the praise or blame of his fellow-men (today: reputation building) (p.164).

Was Darwin an eugeneticist?

It is important to answer this question. Firstly, because only if we come to terms with Darwin's shortcomings, we can hope to discover the moral shortcomings of our time and culture -and correct them. The second reason is simply to be fair to Darwin. Please note that Darwin did not use the word 'eugenic' himself. Galton used the word 'eugenic' after Darwin's death in Inquiries into Human Faculty and Its Development (1883). However, let us first check the most debated passage (10) in Descent:
"Natural Selection as affecting Civilised Nations — I have hitherto only considered the advancement of man from a semi-human condition to that of the modern savage. But some remarks on the action of natural selection on civilised nations may be worth adding. This subject has been ably discussed by Mr. W. R. Greg (9), and previously by Mr. Wallace and Mr. Galton (10). Most of my remarks are taken from these three authors. With savages, the weak in body or mind are soon eliminated; and those that survive commonly exhibit a vigorous state of health. We civilised men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed, and the sick; we institute poor-laws; and our medical men exert their utmost skill to save the life of every one to the last moment. There is reason to believe that vaccination has preserved thousands, who from a weak constitution would formerly have succumbed to small-pox. Thus the weak members of civilised societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man. It is surprising how soon a want of care, or care wrongly directed, leads to the degeneration of a domestic race; but excepting in the case of man himself, hardly any one is so ignorant as to allow his worst animals to breed.

The aid which we feel impelled to give to the helpless is mainly an incidental result of the instinct of sympathy, which was originally acquired as part of the social instincts, but subsequently rendered, in the manner previously indicated, more tender and more widely diffused. Nor could we check our sympathy, even at the urging of hard reason, without deterioration in the noblest part of our nature. The surgeon may harden himself whilst performing an operation, for he knows that he is acting for the good of his patient; but if we were intentionally to neglect the weak and helpless, it could only be for a contingent benefit, with an overwhelming present evil. We must therefore bear the undoubtedly bad effects of the weak surviving and propagating their kind; but there appears to be at least one check in steady action, namely that the weaker and inferior members of society do not marry so freely as the sound; and this check might be indefinitely increased by the weak in body or mind refraining from marriage, though this is more to be hoped for than expected."

(From: The Descent of Man, second edition, 1882, chapter 5 (paragraph Natural Selecton as affecting Civilised Nations, page 133-134) on: http://darwin-online.org.uk/ Identifier = F944, F955. (Bold is mine). Also present in the 1th ed. (F937.1)
To analyse this passage completely and fairly I would need more time and space. Therefore, I will focus on –what I think– the most important scientific and moral issues.

What are the scientific issues?

  • Was Darwin right about the hereditability of human characters?
    In the quote above, Darwin uses the words 'hard reason', however his science is weak. For natural selection to have any effect, characters need to be heritable. Is health heritable? Poverty? Susceptibility to small-pox? Darwin did not know. There was no science of genetics in his time! Even worse, Darwin had a wrong theory of heredity: a Lamarckian theory of the inheritance of acquired characters (inherited effects of use and disuse; modification to the direct and prolonged action of changed conditions of life). But even within the framework of a Lamarckian theory of heredity, still the problem of the relative contribution of Lamarckian heredity and heredity in the strict sense exists (11). His Lamarckism probably led him to overestimate the role of heredity and underestimate the role of the environment (vaccination, education, poverty). He neglected the role of the environment (education, medical care, etc) in the improvement of human wellfare. And that led him to overestimate the hereditary damage ("highly injurious to the race of man"). He viewed the damage as irreversible and not capable of medical treatment.
  • Was Darwin justified in applying natural selection to humans?
    Yes, because natural selection is applicable to all life, including humans and including mental characteristics. Wallace denied that natural selection was responsible for the mental faculties. In that respect Darwin was more consistent.
  • Was Darwin justified in applying the principles of artificial selection to humans?
    Artificial selection of domesticated animals and plants involve purposeful selection with a specific goal -a property- in mind. Humans are not bred at all, however Darwin was justified in assuming that animals and humans have the same type of heredity and therefore will react in a similar way to selection, natural or artificial. Some of Darwin's evidence of human heredity came from Francis Galton (1869) Hereditary genius: an inquiry into its laws and consequences.
  • Was Darwin scientifically justified in applying concepts such as 'weak in mind and body' in humans?
    In general concept such as 'weak in mind and body' and others (12) are too imprecise to be scientifically usefull, although it seems to be common in his time. However, specific examples such as short-sightedness (p. 33, 2nd ed), "the inferiority of Europeans" has a sufficiently clear medical meaning. Incidently, it shows that Darwin does not hold that Europeans are superior in every respect (13).

What are the moral issues?

"Are you an inferior member of society?". What would you answer if a researcher asked you this question? I guess you would say: "Of course not!". This illustrates two problems: the meaning of 'weak' and 'inferior' was culturally defined (14), (Darwin was a member of the well educated and rich upper class of his society), and at the same time a value judgement (normative statement). 'Inferior' is a negative value. Scientific statements should be descriptive and as objective as possible, never normative or subjective. In Darwin's writings the descriptive and normative statements are not clearly separated. It needs further study to determine whether the distinction fact - value was known in his time. Anyhow, the phrase 'inferior members of society' was still present in the 1882 second edition (1, p.134, p.140) despite many other corrections. It seems that his readers did not object to it so strongly.


It was a real suprise for me to discover in Descent of Man how much Darwin understood of social behaviour, altruism and morality. Having read modern ethologists such as Frans de Waal, it struck me how much they confirm or –if you wish– repeat Darwin's views and explanations. Moreover, it seems some scientists even don't know that they are repeating Darwin. On the other hand, when Darwin applies natural selection and heredity to humans, his views are outdated and his language is sloppy and uncongenial ('higher', 'lower', 'superior', 'inferior', 12). However, if we use the definition:
'Eugenics is a social philosophy which advocates the improvement of human hereditary traits through various forms of intervention" (wiki)
and if we accept Darwin's goal of the paragraph, namenly 'the study of the effects of Natural Selection on Civilised Nations' then this paragraph is not advocating eugenics. Studying the effects of natural selection on human beings is just as scientific as studying the effects of natural selection on animals and plants. Ultimately, Natural Selection results in adaptation. There is nothing wrong with that.
Although Darwin's views could be elaborated into some eugenic political system, Darwin himself did not do antything of the sort. He rejected any forced State interference with human reproduction. He did not write pamphlets, articles or books to promote eugenics. The reason is clear:
"if we were intentionally to neglect the weak and helpless, it could only be for a contingent benefit, with a certain and great present evil." (p.169).
In fact Darwin only wrote a few paragraphs, which were heavily based on other authors. Indeed, Darwin was not deeply interested in eugenics. After the publication of The Descent he wrote The Expression of the Emotions in Man and Animals and The formation of vegetable mould, through the action of worms, with observations on their habits. The label 'eugeneticist' is far more appropriate for scientists as Francis Galton and Ronald Fisher, who both were influenced by Darwin, but went further than Darwin.


  1. First edition, http://darwin-online.org.uk/ (F937). Second editon (F955). These online versions are invaluable, especially the Search utility which enables a word search throughout the whole book. This is a huge advantage over the printed edition. Also the first and second editon can easily be compared.
  2. Frans de Waal wrote the following books: 'Our Inner Ape', 'Primates and Philosophers: How Morality Evolved', 'Chimpanzee Politics: Power and Sex among Apes', 'Good Natured: The Origins of Right and Wrong in Humans and Other Animals', 'Peacemaking among Primates'.
  3. I was encouraged to read The Descent by philosopher Herman Philipse (Utrecht University, The Netherlands). The program of his lectures Ethiek en Evolutie (Ethics and Evolution) is here (Dutch), each lecture has a summary (pdf) in Dutch.
  4. For example: warning each other for danger (sentinels) (p.74), wolves hunting together (p.75), sympathy for members of the group (p.76), obedience to groupleader in baboons (p.79).
  5. This definition of general good does not exclude polygamy or a large harem because that system could produce as many children as universal monogamy.
  6. Please note, this is group selection which is a controversial explanation today. However, Sober and Wilson (7) defend it forcefully.
  7. For example Darwin writes "the great sin of slaverny" (p.94). The abolishment of slaverny is an example of moral progress.
  8. Elliott Sober and David Sloan Wilson (1999) Unto Others. The evolution and psychology of unselfish behavior, page 4.
  9. Here I disagree from Darwin and many contemporary scientists. Darwin writes about the human colonization of the earth: "He manifestly owes this immense superiority to his intellectual faculties, his social habits, which lead him to aid and defend his fellows" (p.137) is naive. I would say: human brutality -his readiness to exploit, conquer, kill- did allow him to colonise the earth. "At the present day civilised nations are everywhere supplanting barbarous nations" (p.160) is also naive.
  10. The passage is discussed by George Levine (2006) Darwin Lovews You. Natural Selection And The Re-enchantment Of The World, chapter 2, pp 61-72. Levine stops the quote at "... worst animals to breed" which is a pity.
  11. Darwin knows about the distinction: "This immunity in the negro seems to be partly inherent, depending on some unknown peculiarity of constitution, and partly the result of acclimatisation". (1, 2nd, p.193)
  12. Other inappropriate words used by Darwin: reckless, improvident, vice, careful, frugal, virtuous, reckless, degraded, vicious, weak, savages, barbarians, brutes, useless, enervated, corrupt, licentiousness, decency, and statements such as: "Thus the reckless, degraded, and often vicious members of society, tend to increase at a quicker rate than the provident and generally virtuous members." (1, p.138)
  13. This passage show the superiority of Europeans: "The western nations of Europe, who now so immeasurably surpass their former savage progenitors, and stand at the summit of civilisation, ..." (1, p.141).
  14. Those who accuse Darwin of immoral views would be advised first to have a look at what the Founding Fathers said about the original inhabitants of America. See: Robert Trivers (2011) Deceit and Self-Deception: Fooling Yourself the Better to Fool Others, chapter 'False Historical Narratives'. For example:
    • President Thomas Jefferson (1743 – 1826): "This unfortunate race, whom we had been taking so much pains to save and to civilize, have by their unexpected desertion and ferocious barbarities justified extermination and now await our decision on their fate". p. 221.

       Further Reading  

  • Books by Charles Darwin (on this site).
  • See also politics, ethics & evolution for a list of other books on this site.
  • Leonard Darwin is the son of Charles Darwin and wrote What is Eugenics?, Watts & Co, 1928. (the wiki article does not mention the book).
  • Jan A. Witkowski and John R. Inglis, Eds Davenport's Dream. 21st Century Reflections on Heredity and Eugenics. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 2008. 520 pp.
    Reviewed in Science 25 juli 2008: "Yet because of the essays, I am pleased to recommend the volume to the broadest possible audience. ... No one can say which (if any) human genetic variants will survive the anthropocene epoch we have just entered. Therefore eugenics was and remains a dead end, and it cannot be the answer.".
  • Adrian Desmond, James Moore (2009) Darwin's Sacred Cause: How a Hatred of Slavery Shaped Darwin's Views on Human Evolution, Houghton Mifflin Harcourt. Very important (see title of the book!).
  • Alain Marciano and Roger Koppl (2009) 'Darwin, Darwinism and Social Darwinism', Journal of Economic Behavior & Organization, Volume 71, Issue 1, Pages 1-74 (July 2009)
  • Paul Ekman (2010) 'Darwin's Compassionate View of Human Nature', JAMA February 10, 2010. Vol. 303 (6): 557-558. pdf:
    "Darwin's thinking about compassion, altruism, and morality certainly reveals a different picture of this great thinker's concerns from that often portrayed by those unacquainted with his writings who focus on the catchphrase the survival of the fittest ".
  • Darwin against cruelty to animals: An appeal, http://darwin-online.org.uk/; F1931.
  • Darwin was against vivisection: Letter on Vivisection.

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Copyright ©G. Korthof 2008 First published: 26 Apr 2008 Updated: - F.R./N: 14 Nov 2012