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1. The Continuity of Man and Animals

Today, I wish to talk about Darwin's biological considerations on morality. There are other people who treated the same or the related problems in the 19th century, e.g. Spencer or Huxley; but it seems to me Darwin is by far the most important. When I began to study the Darwininan evolutionary theory some twenty years ago, I was very much impressed by Darwin's persistence with his thesis of the continuity of man and animals. In The Descent of Man, published in 1871 (2nd ed., 1874), this thesis is put forward as follows [Q1]:

It has, I think, now been shewn that man and the higher animals, especially the Primates, have some few instincts in common. All have the same senses, intuitions, and sensations,----similar passions, affections, and emotions, even the more complex ones, such as jealousy, suspicion, emulation, gratitude, and magnanimity; they practise deceit and are revengeful; they are sometimes susceptible to ridicule, and even have a sense of humour; they feel wonder and curiosity; they possess the same faculties of imitation, attention, deliberation, choice, memory, imagination, the association of ideas, and reason, though in very different degrees. The individuals of the same species graduate in intellect from absolute imbecility to high excellence. They are also liable to insanity, though far less often than in the case of man. (Descent of Man, ch. 3)

However, traditionally, there have been various sorts of arguments for regarding man as qualitatively distinct from any other animals; among these arguments, it seems that the most persuasive was that only man has the moral sense or conscience. For instance, Rev. Leonard Jenyns, commenting on the Origin of Species in a letter to Dawin, argues as follows [Q2]:

One great difficulty to my mind in the way of your theory is the fact of the existence of Man. I was beginning to think you had entirely passed over this question, till almost in the last page I find you saying that "light will be thrown on the origin of man and his history." By this I suppose is meant that he is to be considered a modified and no doubt greatly improved orang! . . . .
Neither can I easily bring myself to the idea that man's reasoning faculties and above all his moral sense could ever have been obtained from irrational progenitors, by mere natural selection ----acting however gradually and for whatever length of time that may be required. This seems to me doing away altogether with the Divine Image that forms the insurmountable distinction between man and brutes. (Letter to Darwin, Jan.4, 1860. Wilson, 1970, 351.)

Thus Darwin had to face with the problem of how we can handle the moral sense within evolutionary processes, in other words, how we can give a biological explanation for man's moral faculties. This subject is tackled in chapters 4 and 5 of his book.

2. Social Instincts

Darwin's explanation of the origin of the moral sense is very interesting, but as is customary with his exposition, it is very complicated and hard to follow. But I think the main line of his argument may be reconstructed as follows: First, he puts forward the following conjecture or hypothesis [Q3]:

(H) "any animal whatever, endowed with well-marked social instincts, the parental and filial affections being here included, would inevitably acquire a moral sense or conscience, as soon as its intellectual powers had become as well, or nearly as well developed, as in man." (op. cit., ch. 4)

"Oh, come on, this is a sheer counterfactual statement, and how should we justify such a statement?"-----no doubt many people may feel this way. But let's see what he means. Darwin means that this statement can be justified or made probable by what we know about man and social animals in general, if we supply evolutionary considerations.

First, he reminds us of a fact that man is a social animal: human beings live in a family, in a group, and in a society; and this is a biologicalfact like that bees and ants live in a colony. And any social animal has social instincts which support their social life. By "social instincts" he means innate or genetic propensities "to take pleasure in the society of its fellows, to feel a certain amount of sympathy with them, and to perform various services for them" (ibid.). Since social instincts are part of the "essence" of a social animal, so to speak, these instincts persist and work continually in the whole life of any individual. But these instincts may work quite differently depending on what species that animal belongs to: in the case of bees and ants, social instincts may determine particular jobs and roles an individual is to perform; but in a higher animal, social instincts may work as a mere tendency to prefer social life and to aid fellow members.

Of course, it may be asked why these animals have such instincts. Darwin has a ready answer to this: such instincts are useful for these animals, and therefore they have acquired these by natural selection. But we have to notice here that the moral sense is not included in social instincts at this stage of the argument. Darwin's purpose is to depict the process by which the complex faculty of moral sense may be developed from the combinations of simpler faculties of social instincts and intelligence, hopefully by means of natural selection. Moreover, even if we admit his assumption that the social instincts are useful for the animals, there is still a crucial problem: useful exactly to whom?----to a group of animals or to individual animals? We will come back to this problem later (Section 5).

3. Conflicts of Social Instincts with Other Instincts

Now, granted that man is a social animal, how has man acquired the moral sense?The second stage of Darwin's argument is concerned with an imaginary psychological process which may give rise to something like moral sense or moral feeling. Suppose some social animal has acquired high intelligence so that it canremember past actions and motives. This will intensify the ability of sympathy which is included in the social instincts. Sympathy is an ability to re-present others' feelings, as well as one's own, within oneself; so that if this animal acquires better knowledge about others, by means of its improved intelligence, it is natural to suppose that the extent of sympathy will also be somehow widened.

But Darwin is not arguing that, since intelligence strengthens the operation of sympathy, the social instincts together with intelligence give rise to the moral sense. The matter is not that simple. We have to notice that the social instincts are not necessarily the strongest in each occasion when this animal makes decisions or actions, and they may give in to some other temporarilystronger motives, such as appetites or sexual drive. As we all know, we humans have anti-social or selfish motives as well as social motives; we often follow the former, and with higher intelligence we may even become cleverer for satisfying our selfish motives rather than social motives. Darwin is well aware of this. Then what would give rise to the moral sense?

The key is the enduring nature of the social instincts. The social instincts
may give in to other stronger motives; but nevertheless, the social instincts are ever persistent. Then what would happen when these social instincts conflicted with other desires and were frustrated by satisfying the latter? As we know, when a certain instinct or desire failed to be satisfied, some sort of disagreeable feeling remains. And since the social instincts are enduring, each time this animal recall this conflict, this disagreeable feeling also recurs and it may be even intensified. Thus in memory, those feelings which are associated with social instincts would become dominant. Similar things would happen with agreeable feelings of satisfaction and enjoyment; if this animal followed the social instincts rather than other desires, its satisfaction would be recalled with enjoyment, because that is quite in conformity with its enduring social nature. And this is the beginning of the formation of moral feelings; and the ability to experience these feelings is an essential part of what we call the "moral sense".

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[Note added in October 1998: This argument was already criticized in the 19th century as trying to replace an evolutionary explanation of the origin of morality by a mere "imaginary psychology" (Shurman 1887, ch.5); and this crriticism seems to have some point. However, we can reconstruct Darwin's argument in two stages, (1) the evolution of a behavioral strategy, and (2) the evolution of psychological properties accompanying such a behavioral strategy.

As regards (1), the contemporary reader is already familiar with the conditions under which an "altruistic" (or "conditionally altruistic") strategy can evolve and become dominant within a group. For instance, for reciprocal altruism, two conditions are necessary: (i) the same individuals must interact frequently, and (ii) they must have memory in order to respond to an opponent's previous response. We should notice that Darwin's conditions can cover these two; i.e., social instincts imply frequent interactions, and intelligence provides the memory needed for a wise strategy. I have shown, by a simple example, how a social and intelligent animal may acquire an altruistic strategy by natural selection (Uchii 1998).

As regards (2), it is quite natural to suppose that such a behavioral strategy needs some psychological makeup which supports it; in an animal with social instinct and intelligence, feelings, preferences, or propensities will accompany a behavior or a response to an opponent's action. And it is not difficult to imagine what sort of feelings are necessary for a reciprocal altruism, and this can be confirmed, to a considerable extent, by observing primates's behavior (see de Waal 1996). Thus, we can perfectly make sense of Darwin's original argument.]

4. Social Norms, Sympathy, and Habits

Darwin's emphasis on the persistent nature of the social instincts is illuminating. But his story is not over. Darwin next points out that high intelligence would be accompanied by the ability to use some sort of language, which would enable our animal to express their wishes or desires as a member of their community. Thus it is very likely that they come to form their social norms, or "public opinions" as to how they should do for the common benefit of the community. These norms or opinions are of course in an important sense "artificial" or "conventional"; and therefore these cannot be regarded as genetically determined. Darwin admits all this. But he emphasizes that "however great weight we may attribute to public opinion, our regard for the approbation and disapprobation of our fellows depends on sympathy, which . . . forms an essentialpart of the social instinct, and is indeed its foundationstone" (op. cit., ch. 4). His point seems clear: although the contents of norms and public opinions are determined largely by artificial factors, their binding force essentialy depends on a biological factor, i.e. sympathetic ability, and this is instinctive or genetically determined.

The importance of sympathy has been emphasized by many philosophers such as Adam Smith or Hume. But Darwin criticizes these philosophical views as follows: we have to understand sympathy not merely as a psychological ability to reproduce former states of pain or pleasure, but also as a biological instinct, which is a product of evolution. Only the latter characterization can explain the fact that "sympathy is excited, in an immeasurably stronger degree, by a beloved, than by an indifferent person" (ibid.). This point is of course frequently mentioned by recent sociobiologists; but I wish to emphasize that Darwin was well aware of this, and he clearly saw its significance for ethics, although he was not clear about the biological mechanism which produces such tendencies.

By now, the major part of Darwin's view on the genesis of the moral sense or conscience has been outlined. Let me summarize his view with his own words [Q4]:

At the moment of action, man will no doubt be apt to follow the strongest impulse; and though this may occasionally prompt him to the noblest deeds, it willmore commonly lead him to gratify his own dsires at the expense of other men. But after their gratification when past and weaker impressions are judged by the ever-enduring social instinct, and by his deep regard for the good opinion of his fellows, retribution will surely come. He will then feel remorse, repentance, regret, or shame; . . . . . He will consequently resolve more or less firmly to act differently for the future; and this is conscience; for conscience looks backwards, and serves as a guide for the future. (op. cit., ch. 4)

In short, his explanation of the genesis of conscience has the following features: (1) it analyzes conscience into a bundle of psychological dispositions and feelings; (2) these dispositions and feelings are products of evolution and therefore are instinctive, i.e. they have a genetic basis; and (3) because of this, the wrokings of conscience have some conspicuous limitations that the conscience regulates mainly actions toward closer people.

The rest of his arguments is an elaboration of the preceding view. Darwin was a good observer, and it seems that this ability is well displayed in his remarks on the interplay between sympathy, public norms, and individual habits in morals. He argues that the preceding view is quite in accord with what we know about undeveloped people. Among them, only strictly social virtues are esteemed, and self-regarding virtues such as temperance or prudence are rather neglected. Darwin seems to attribute the development of self-regarding virtues mainly to the improvement of intelligence and knowledge; but he is also aware of the importance of habits of individuals. As many moral philosophers have emphasized, virtues must be acquired as a habit; and a substantial part of habits may originate from individuals and spread within their groups, and sometimes beyond their groups, by imitation. This is one of the essential features of what we call "culture". And such habits often strengthen and complement the workings of social instincts. Here, biological process merges into cultural process. This is a very intriguing question, but we shall not get into this.

5. Darwin on Group Selection and Kin Selection

Now, what has Darwin accomplished by his argument so far? For the sake of argument, let us suppose that his explanation of the genesis of conscience is on the right track. But where does the principle of natural selection play its role? This still is not quite clear. Since Darwin attributed the genesis of conscience mainly to two factors, (1) intelligence and (2) the social instinct,we will examine the two in this order.

First, it seems quite clear that intelligence is developed by means of natural selection; because intelligence is no doubt useful to its possessor, an individual animal. So we can agree with Darwin's assertion, at least with respect to this factor.

But what about the social instinct? The social instinct included sympathy, in particular, and sympathy played a crucial role in generating the moral sense or conscience. By means of sympathy, individual animals care for others and restrict their own selfish desires; in other words, altruistic or moral tendencies originate from sympathy. Then naturally we have to ask: Is the social instinct including sympathy also developed by natural selection? Darwin's attitude to this question is ambivalent; sometimes he seems to think that the answer is obviously 'yes', but at other times he seems to be aware of a grave difficulty. But what exactly is this difficulty? Let me explain.

Let us recall how natural selection works. There are many individual variations which are hereditary among animals of the same species. And if some of these variations are more advantageous than others in the struggle for existence, individuals with these variations gradually increase within the species, and they eventually become dominant in number. Thus natural selection works in terms of the herediatry characteristics of individuals; and these characteristics must be useful primarily to their possessors, i.e. to individuals. But Darwin frequently speaks of moral faculties useful to a tribe or group of individuals, and he says that these faculties have been developed by the competition among such tribes or groups in their struggle for existence. For instance, he argues this way [Q5]: "When two tribes of primeval man, living in the same country, came into competition, if . . . the one tribe included a great numberof courageous, sympathetic and faithful members, who were always ready to warn each other of danger, to aid and defend each other, this tribe would succeedbetter and conquer the other" (ch. 5). Granted; but is this natural selection working on individuals? Darwin doesn't seem to think it is; for he is well aware of the difficulty as follows [Q6]:

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, and how was the standard of excellence raised? It is extremely doubtful whether the offspring of the more sympathetic and benevolent parents, or of those who were the most faithful to their comrades, would be reared in greater numbers than the children of selfish and treacherous parents belonging to the same tribe.. . . Therefore it hardly seems probable, that the number of men gifted with such virtues, or that thestandard of their excellence, could be increased through natural selection, that is, by the survival of the fittest; for we are not here speaking of one tribe being victorious over another. (ibid.)

Thus Darwin's program for explaining the genesis and development of morality by means of natural selection seems to have failed at a crucial point. That is to say, he tried to appeal to what we now call 'group selection' (i.e. an advantageous group survives and individuals of that group indirectly change), but he admitted that this group selection is not likely to be supported by natural selection working on individuals.

However, it must be pointed out, to be fair to Darwin, that he was aware of at least one key for solving this difficulty. It is what we now call 'kin selection.' Just before discussing the development of moral faculties, Darwin argues for the development of intelligence by natural selection, and he briefly touches on this key, as follows [Q7]:

If such men [i.e. intelligent men] left children to inherit their mental superiority, the chance of the birth of still more ingeneous members would be somewhat better, . . . Even if they left no children, the tribe would still include their blood relations; and it has been ascetained by agriculturarists that by preserving and breeding from the family of an animal, which when slaughtered was found to be valuable, the desired character has been obtained. (ibid.)

This idea could have been more developed and applied to the explanation of moral faculties; but Darwin left that job to the biologists in the 20th century, such as W. D. Hamilton (kin selection) or Robert Trivers (reciprocal altruism). What Darwin actually did instead was to appeal to the principle of heredity of acquired characters.

6. The Significance of Darwin's Considerations on Morality

In this talk I have outlined what I take as the essence of Darwin's theory of morality. He was mainly concerned with the biological and psychological task of explaining the genesis of moral faculties of man. But it seems to me that he was also interested in moral philosophy based on the evolutionary theory. The major advocate of what is called 'evolutionary ethics' in the 19th century was of course Herbert Spencer; and Darwin was far more cautious than Spencer, trying to avoid any definite statements about what we ought to do. But now and then he criticizes former and contemporary moral philosophers, such as Adam Smith or John Stuart Mill, and sometimes even gets into issues of eugenics, in The Descent of Man. This indicates Darwin's strong interest in moral philosophy. Moreover, we have good evidence that this interest originates in his youth. For instance, I was surprised by finding the following remarks (written in October, 1838) in his Notebooks [Q8]:

Two classes of moralists: one says our rule of life is what will produce the greatest happiness.---The other says we have a moral sense.---But my view unites both & shows them to be almost identical. What has produced the greatest good or rather what was necessary for good at all is the instinctive moral senses: (& this alone explains why our moral sense points to revenge). In judging of the rule of happiness we must look far forward & to the general action---certainly because it is the result of what has generally been best for our good far back.---(much further than we can look forward: hence our rule may sometimes be hard to tell). Society could not go on except for the moral sense, any more than a hive of Bees without their instincts. (Old & Useless Notes 30, Barrett et al., 1987, 609.) [→Darwin in 1840, drawing by the author]

We may recall that the moral philosophers who emphasize the moral sense are called 'Intuitionists' and those who emphasize the greatest happiness are called 'Utilitarians'. Thus the young Darwin here is claiming that he can synthesize these two major schools of moral philosophy! I will add, for your curiosity, that Henry Sidgwick, a great utilitarian and who claimed that Intuitionism and Utilitarianism can coincide, was born in the same year, 1838. And we have to notice also that Darwin's idea of the genesis of morality is already sketched in rough outline in the last sentence.

But these historical interests aside, are there any significant suggestions for ethics or normative moral philosophy that can be exploited from Darwin's theory of the moral sense? I think there are. Since I do not have much time left, let me briefly touch on this without arguments. First of all, (1) we have to know well about human morality in order to make any normative assertions. And in this respect, the Darwininan view of morality is certainly useful. We have to construct feasible ethics for humans as a social animal, not for an angel or an isolated beast. For this purpose, we certainly have to know our biological capacity, limitations as well as potentialities.

Secondly, (2) if the Darwinian view is on the right track, we should take the continuity of man and animals more seriously. Darwin argued more or less persuasively that we humans and other animals share many properties, including intelligence, feelings and preferences. Hence, if we find some of these valuable and think that they should be protected by our morals, the same consideration should support similar treatments of animals, with the difference of various degrees, of course. For instance, persons like Jane Goodall, knowing very well about primates, assert that our treatment for them should be improved; and this assertion may well be justified.

Thirdly and finally, (3) the Darwinian view suggests a certain approach to ethics, say the Reductionist approach (I borrow this word from Parfit, who uses it in the context of the problem of personal identity; and Daniel Dennett also defends this approach, with respect to cognitive science, in his Darwin's Dangerous Idea, 1995). This is the view that all ethical concepts can be analyzed into more basic concepts which are not themselves ethical. In other words, it is the view that concepts such as 'conscience' or 'moral goodness' will be well understood only in terms of concrete workings of human faculties and feelings, without postulating any peculiar realm of moral value. This is exactly what Darwin has done in his theory of the moral sense; conscience or moral sense is so called because of its workings in a certain way, not because it is related to some irreducible moral value. Since this position is very likely to be misunderstood, I will hasten to add a few explanatory remarks.

By reductionism I do not mean that ethical or evaluative concepts can be reduced to factual or descriptive concepts; this is what Moore called 'naturalism' and I do not support it. In order to be a reductionist in my sense, one need not be a naturalist. All one has to admit as an ethical reductionist is that morality can be related to a bunch of natural or conventional elements and their workings. Morality needs intelligence, but this intelligence does not come from any peculiar realm, devine or angelic. Morality needs some instinctive factors, but one can find similar factors in other animals. And, again, moral feelings and preferences have an origin in a non-moral animal world, and you don't have to suppose any peculiar 'respect for the divine moral law'. All the factors necessary for full understanding of morality can be found in this world and the workings of its constituent parts. This is what I mean by reductionism.

And I understand that Darwin is one of the most powerful advocates of this position, although very few people would regard him as a moral philosopher. So, by emphasizing his contribution to ethics as a reductionist, I should like to end my talk.

Bibliography

Barrett, P.H. et al., eds. (1987) Charles Darwin's Notebooks, 1836-1844, Cambridge: Cambridge University Press, 1987.

Darwin, C. (1871) The Descent of Man, 1st ed., London: Murray, 1871.

Darwin, C. (1874) The Descent of Man, 2nd ed., London: Murray, 1874. (1922 reprint is used.)

Dennett, D.C. (1995) Darwin's Dangerous Idea, Simon and Shuster, 1995.

de Waal, Frans (1996) Good Natured, Harvard University Press, 1996.

Parfit, D. (1984) Reasons and Persons, Oxford University Press, 1984.

Shurman, J.G. (1887) The Ethical Import of Darwinism, Charles Scribner's Sons, 1887; 3rd. ed., 1903.

Uchii, S. (1996) Evolutionary Theory and Ethics [in Japanese], Kyoto: Sekaishiso-sha, 1996. →English abstract

Uchii, S. (1997) "The Origin of Morality" [in Japanese], Kagaku (Science Journal) 67-4, 1997. →English abstract

Uchii, S. (1998) "From the Origin of Morality to the Evolutionary Ethics, part I" [in Japanese], Tetsugaku Kenkyu (Journal of Philosophical Studies) 566, October 1998. →English abstract

Uchii, S. (1999) "From the Origin of Morality to the Evolutionary Ethics, part II" [in Japanese], Tetsugaku Kenkyu (Journal of Philosophical Studies) 567, (forthcoming)1999. →English abstract

Wilson, L.G., ed. (1970) Sir Charles Lyell's Scientific Journals on the Species Question, New Haven: Yale University Press, 1970.

Postscript

This is a paper read for a session on 19th Century Biology, International Fellows Conference (Center for Philosophy of Science, Univ. of Pittsburgh), May 20-24, 1996, Castiglioncello, Italy.

Robert Butts was the commentator; his comments and questions from the floor mostly centered on what I didn't say in the paper, i.e. on the point how scientific knowledge of evolution and normative ethics are related. I have worked out my ideas in my book (1996, see the preceding Bibliography, and click here for English abstract); the essential idea is that (1) evolutionarty biology can teach us what sort of sentiments or preferences we have as part of our human nature, and (2) moral sentiments and preferences are among them. Since, as I see it, the justification of moral judgements can be made essentially in terms of our rational choice for satisfying our preferences (not all, but those that can survive criticisms by facts and logic)----including moral preferences----, evolutionary knowledge, unlike knowlege of general relativity or quantum mechanics, does contribute to our normative ethics. For a brief discussion of the justification of "ought" statements (prudential, moral, etc.), see my paper "Comments on Prof. Ruse's View" in Newslet. 19.

Finally, I wish to thank Jerry Massey for teaching me de Waal's recent book (1996) on the origin of morality; I have supported my view by de Waal's observations in my 1997 and 1998 papers.