Issues at stake in eighteenth-century racial classification

1. Eighteenth-century racial classification has been much studied, and my aim here is not to give another general view of the question. Instead, I want to look at an interconnected set of questions involved in, and some of the problems raised by, this type of thinking about human varieties – which I hope will help to bring out some of the issues at stake and their ramifications, in particular the link between the question of racial classification and aspects of more general thinking about human beings in the period.
The issues I want to raise revolve to a large extent around the religious implications, in a wide sense. The first aspect of this concerns the link with the slave trade andthe abolitionist campaign of the late Eighteenth Century which, as has often been pointed out, is a significant factor in the background to the development of systems of racial classification. One should be wary of generalisations as to the effect of thisabolitionist movement on thinking about human diversity, but there is one issue where the question of slavery seems to loom large. I am referring to the discussion of the factors determining racial difference, and essentially the question of whether theywere the result of inherent distinctions or of what appeared to be acquired characteristics, the result for example of climate and geography. On the one hand, monogenecists naturally favoured the former hypothesis, and it was as a result widely used by abolitionists, for a central, and in their eyes vital, aspect of their arguments against slavery was the insistence – frequently linked to Biblical teaching – that all humans were of the same origin, which does not mean that polygenecists were necessarily defenders of slavery; indeed the cases of Voltaire, Hume, or Kames, show the opposite. But I want to link this debate to that found among materialists who were concerned with the relative influence of inherent physical “organisation”, external factors like climate, and “moral” factors such as education, the state of society and so on in determining not only individual character but also mental capacities. I shall thus look at the link between such arguments and those concerning human groups rather than individuals, and the extent to which a form of materialism could be seen to have favoured physical anthropology which classified humans in terms of differences in physical structure, and, perhaps, a form of polygenesis. Another aspect of the question concerns the dividing-line separating humans and animals; for the materialists’ blurring of the distinction between humans and other animals could be seen to have implications for the debate on human diversity.

2. These aspects are obviously all interrelated, but for thesake of clarity, I shall try to take the issues separately. We shall thus begin with the debate on the influence of climate or of other accidental factors in determining physical characteristics. To show the link between this question and that of polygenesis, one can do no better than to quote the remark made by the scientist P.L. Moreau de Maupertuis in his Vénus physique (1745), which was a revised version of a dissertation published the previous year called Dissertation physique à l’occasion du nègre blanc. Here, after having explained his theory of reproduction based on the combination of parts contained in the seminal liquid of each partner, he used this theory to explain the colour of Negroes by the inheritance of acquired characteristics. For him, white was the original colour of humanity and “ce n’est que par quelque accident que le noir est devenu une couleur héréditaire aux grandes familles qui peuplent la zone torride”. What is significant is what he concludes from this, namely that we can forget “cette difficulté donc sur l’origine des Noirs tant rebattu et que quelques gens voudraient faire valoir contre l’histoire de la genèse qui nous apprend que tous les peuples de la terre sont sortis d’un seul père et d’une seule mère”.^[1] Thus the link between belief in the accidental appearance of the black colour and the opposition to polygenesis is very clearly made. It is worth noting that Maupertuis seems to indicate also his opposition to slavery in his Essai de philosophie morale (1749), where we find a remark in the chapter on the Stoics concerning the spiritual strength of Africans seized as slaves who, like ancient philosophers, prefer to die rather than suffer; Maupertuis writes: “Un vaisseau qui revient de Guinée est rempli de Catons, qui aiment mieux mourir que de survivre à leur liberté”.^[2]
Before coming on to discuss in more detail the question of climate, it is worth pointing out that a variety of types of “accidental” factors could be invoked to explain the development of different colours in humans – or more specifically the reasons why blacks were black. The Universal History provides an interesting explanation, again supposing the inheritance of acquired characteristics.

3. Rejecting the recourse to the Biblical account of the curse of Ham, the authors provide the following hypothesis:

The aim is to counter the arguments of the Preadamites and to reconcile the Biblical account of Genesis with the present diversity of races (as is also the case for Maupertuis), by combining the effect of the climate with the hypothesis of the effect of the maternal imagination on the foetus. I do not intend to go into details concerning the debate on skin colour, which has been discussed elsewhere by Renato Mazzolini,^[4] but to concentrate on the debate over the climate.
Arguments for the influence of the climate were of course given added weight by Buffon’s Histoire naturelle (the first volume of which appeared in 1749); in his discussion of humans and description of the different varieties of mankind (a shorter version of which is provided by Diderot’s Encyclopédie article Humaine, espèce), he insists that they are all from same origin, but that differences have come about due to degeneration in some climates as they have moved about and settled in different regions. Although Buffon makes a clear differentiation between humans and animals, between whom there is a barrier,^[5] some humans do seem on the way to animalisation; for example the Eskimos in far North, generally considered as particularly savage, are described as: “une race d’hommes de petite stature, d’une figure bizarre, dont la physionomie est aussi sauvage que les moeurs”, “qui paraissent avoir dégénéré de l’espèce humaine”, and the physical description he gives of them is particularly repulsive.^[6] But despite the clear hierarchy established by Buffon between the beautiful white civilised races of the temperate zone and those savages who have degenerated in more extreme climates, his emphasis on the unity of the human race and his distinction between humans and other animals were extremely influential.

4. His arguments were particularly used to show that Africans were not naturally inferior and fit to be slaves, but that they could improve by different treatment and in a different climate. The abolitionists gave, for example, wide credence to the story, attested by the abbé Demanet’s Nouvelle Histoire de l’Afrique française (1767),^[7] that there existed a Portuguese colony on the West Coast of Africa who had become black over generations, simply due to the effect of climate; this is rather ironical in view of the fact that Demanet, a rather shady character, was both a missionary and the manager of a slaving company in the 1770s. Demanet’s example was in particular quoted and given wider circulation by the Histoire des Deux Indes, and this work’s treatment of the subject of the origin of skin colour is a particularly telling example of the issues at stake. In the first edition of the work, in 1770, influenced perhaps here by Le Cat, the author writes that the attribution of the Negroes’ colour to the climate is “sans fondement”.^[8] In the third edition of the work (1780), however, in which the arguments against slavery are greatly developed, in particular by the addition of a long passage by Diderot, the discussion of the reasons for the colour of the Africans’ skin is likewise greatly extended and the complexity of the question is brought out. And here we see a complete reversal of attitude, for the author adopts the arguments developed in the abolitionist Physiocrat abbé Pierre-Joseph-André Roubaud’s Histoire générale de l’Asie, de l’Afrique et de l’Amérique (1770-75), which expounds Demanet’s theory concerning the effect of both the climate and certain chemical emanations from the soil in determining the colour of the black Africans.^[9] Thus the work now claims that those who rejected climatic explanations were wrong and affirms unambiguously, “que le coloris des nègres est l’effet du climat, de l’air, de l’eau, des aliments de la Guinée”; the proof is: “qu’il change lorsqu’on les conduit dans d’autres nations”.^[10] In addition, the ideological importance of the discussion is emphasized, as the author condemns not only the Biblical explanation for the origin of the Africans, but also the theories of certain scientists who attributed the difference between blacks and whites to the sperm, adding that such a position would allow one to prove “que les nègres sont une espèce particulière d’hommes”.^[11] There is also elsewhere, as we have seen, a reference to the famous colony of Portuguese in the Cape Verde Islands whose decendants “dégénérèrent, avec le tems, de manière à ne guère différer des aborigènes”.^[12]

5. It would be possible to give many more examples of the link made between the effect of climate as expounded by Buffon, with particular reference to Demanet’s black Portuguese colony, and the question of the unity of the human race. The link is overtly made by Georg Forster, who had already referred to Demanet’s claim when he visited the Cape Verde Islands.^[13] And the same connection between the climatic explanation for human varieties and the affirmation, following Buffon, of the unity of the human race is also made some time later by the materialistic medical doctor Cabanis in his Rapports du physique et du moral de l’homme (1802); he too quotes the example of the Portuguese colony in the Cape Verde Islands.^[14] But to confine ourselves to the abolitionists: the example (the Portuguese colony is situated in Sierra Leone, this time) is quoted by the British abolitionist Thomas Clarkson in his Essay on the Slavery and Commerce of the Human Species, in which Clarkson claims that the whole human race was originally of a “dark olive” colour (the colour of Noah and his sons) that was half-way between that of the blacks and the whites, and that humans becameblack or white due to the climate; this is mainly the effect of the sun on the mucosum corpus which determines the colour of the skin. It is in this context that he quotes the Histoire des Deux Indes concerning cases of the children of Africans born in America, who are whiter than their parents, which he says is confirmed by the testimony of “many intelligent Africans”.^[15] Another example he gives concerns the Jews who, although keeping themselves distinct from the rest of the world, differ in colour according to the climate, so that “there appear to be as many different species of Jews, as there are countries in which they reside”.^[16] What emerges from these examples is the overwhelming desire to insist on the unity of the human race by emphasizing the effect of the climate and other environmental causes,^[17] but not necessarily to claim the equality of all humans; for the existence of a hierarchy is not systematically denied but, on the contrary, frequently accepted. This of course was to have long-lasting effects in the Nineteenth Century, when the arguments about climate were countered and the hierarchy was seen to be permanent, as the differences between humans were innate.

6. A particularly important example of such an attitude is provided by the American abolitionist, the Reverend Samuel Stanhope Smith, whose Essay on the Causes of the Variety of Complexion and Figure in the Human Species, published in 1787, argued that racial differences were not fixed and indelible and included an annexe attacking Kames’s Sketches on the History of Mankind. As is indicated by the title, the author discusses at length differences in physical appearance and the reasons for these differences, expounding a relatively complex system to explain the joint effects of the sun, the temperature, “putrid exhalations” from the soil, the environment, way of life, state of society, and so on, with numerous examples, including some of those we have already seen. The aim, of course, is to reject the “arbitrary hypothesis” that humans are derivedfrom different origins. He describes how the progress of civilisation helps to improve physical appearance and lighten the complexion and he believes that Africans become more civilised and beautiful by living in a civilised society. Part of his argumentis based on the differences he claims to see between field slaves and domestic servants in America; he writes, for example:

Like Buffon, he claim that savages have a particular physical appearance and paints the following picture based on his observations of native Americans:

7. Thus moral factors are seen to be as important as climate. This enabled abolitionists to insist that the inferior condition of the slaves in America, although removed from Africa, was due to the treatment they received and thus the very institution of slavery itself. This was particularly the argument developed by the American Benezet in his Historical Account of Guinea (1772): he describes the Africans in Africa as sociable, virtuous people with developed intellectual capacities. Their inferiority in America, which he does not deny, is explained by their servile condition and the contempt they endure, which have made them degenerate and adopt the vices of the Europeans. A similar argument to counter belief in the “innate inferiority” of the Africans is to be found in an anonymous abolitionist pamphlet called Considerations on the Abolition of Slavery and the Slave Trade, which refers to famous examples of slaves with developed intellectual capacities.^[19] We also find the same arguments, concerning the effect of moral factors on the character of the African slaves, used by Diderot in his violent attack on the slave trade contained in a fragment intitled “Sur l’esclavage des Nègres” included in the 1780 edition of the Histoire des Deux Indes. He writes:

8. Another abolitionist writing at the same time but from the opposite side of the religious divide, the Reverend J. Ramsay, insisted at length on the fact that the capacities of the Africans were equal to those of the Europeans and that their present degraded state was the result of a variety of factors, in particular their degree of civilisation in Africa and their treatment in the West Indies.^[22] Finally we should mention the point of view defended by James Dunbar, professor of philosophy at Aberdeen University; in his Essays on the History of Mankind in Rude and Cultivated Ages, not only does he – relatively unusually – reject a hierarchy of colours and show that whiteness is not universally recognised as the ideal of beauty, but he insists on moral factors, claiming that the fact that the slaves are deprived of liberty leads to their physical and moral degeneration, as “the shocks which are felt in the transition from a free and happy state to that of slavery and dejection, may prove, to the last degree, injurious to the organization of man”.^[23] He insists, even more forcibly than many others:

This last example is a particularly strong reminder of the extent to which abolitionists chose to favour “accidental” rather than innate factors when attempting to account for racial differences; conversely, someone like Virey at the beginning of the Nineteenth Century, who considered the Negroes an inherently inferior race destined for slavery, countered at length such arguments and criticised Buffon, with the aim of showing that racial differences were innate and indelible.^[25] Nevertheless nearly everyone seemed to accept the existence of a hierarchy of peoples (with certain exceptions, as we have seen, and here we could also mention the abbé Grégoire), and it was the permanence or otherwise of the observed differences between peoples which seemed important, as the essential point for abolitionists was to defend monogenesis, sanctioned by the Bible.

9. Thus the Reverend James Ramsay, who is particularly concerned to counter irreligious and sceptical tendencies which he claims are extremely fashionable, is at pains to show that the Biblical account is in conformity with experience, reason, analogy and so on. And he particularly warns unguarded writers like Robertson who seem to admit that evidence would point to the different origin of the Americans, for example, if the Biblical account did not teach us the contrary; Ramsay writes:

This brings out particularly clearly the religious background to all these debates. First of all, as is well known, and as we have already seen with the reference to the Preadamites (who, as has been pointed out by by Giuliano Gliozzi,^[27] were polygenecists but not at all necessarily racists), the calling into doubt of the Biblical account of the single origin of all humans could be an aspect of heterodox or anti-religious thinking, although here again one must be careful of generalisations, as there were attempts to reconcile the Bible with polygenesis.^[28] But the anti-Biblical bias is clearly evident in the case of Voltaire. The connection is pointed out by J. Beattie in the attack on David Hume and scepticism in his Essay on the Nature and Immutability of Truth, first published in 1770. He claims, with reference the infamous note Hume added to his “Essay on National Characters”, that “the natural inferiority of negroes is a favourite topic with some modern writers” because they “mean perhaps to invalidate the authority of the Book which declares, that “Eve was the mother of all living” and that “God hath made of one blood all nations of men, for to dwell on all the face of the earth”. He also insinuates that some of them want to vindicate slavery, which he calls “a certain barbarous piece of policy”.^[29] We see here a direct link made between questions of racial classifiction, the defence of slavery and religious heterodoxy. It is these implications that I would like to explore now.
As we have seen, there are two aspects of Buffon’s legacy which played an important role in racial discussions of the Eighteenth Century: on the one hand the unity of the human race,as the different varieties of mankind had degenerated from the original white colour due to climatic and other factors; and on the other, the clear distinction made between humans and the animals, however much certain animals, in particular the higher apes, might seem to be similar to humans. Both these principles seemed to be undermined in the Eighteenth Century by aspects of the thinking of those who rejected the teaching of the Churches concerning humans, and in particular those who developed a materialistic conception of human beings, that is, who denied the existence of an immortal soul and who attempted to explain all of human capacities by matter alone. I cannot here go into details concerning these thinkers in general; I shall limit myself to the particular question under discussion, whose importance has already been pointed out by Carminella Biondi.^[30]

10. The first point to be noticed is that arguments for the materiality of humans depended to a large extent on comparative anatomy and examples of the similarities between humans and animals, essentially their brains. The aim was to demonstrate that if one denied an immortal soul to animals, then one must deny it to humans as well, and vice versa. The argument from comparative anatomy, to show that humans were animals like any other, was particularly used by one of the most outspoken of materialists from the first half of the century, J.O. de La Mettrie, who famously declared that if one could teach a great ape or orang-outan to speak (which he seemed to think might be possible) then there would be no difference betsween it and a human being.^[31] This essential unity of all animals, which adopted the old idea of the great chain of being, was particularly developed by Diderot, who repeatedly emphasized the unity of all of nature and denied, going much further than Buffon, the existence of true barriers enabling one to define species or anything other than individuals. Thus he wrote, in his Encyclopédie article Animal, which also contained clearly materialistic implications, that the general categories of animal or vegetable are arbitrary,^[32] and he emphasized the way that the capacity for thought develops as the organism develops throughout the chain of beings:

Thus it is difficult to pinpoint a place in the scale where “animality” begins. For him, in addition, as nature was dynamic, in constant mutation, a fixed system of classification was impossible. He wrote in his Pensées sur l’interprétation de la nature:

11. It is interesting to note that in order to support this point of view he appealed to Peter Camper’s physiology and the use of the measurement of the facial angle to determine “racial” differences; and in so doing, Diderot interpreted Camper’s ideas to fit in with his own. For despite the Dutchman’s drawings illustrating facial angle, which seem to indicate a continuity in the gradually increasing facial angle, from animals to humans, up to the most perfect classical Greek model, Camper followed Buffon in insisting on a sharp dividing line between humans and animals, saying that great apes could never walk upright or speak.^[35] This did not prevent Diderot from asserting, incorrectly, in his ƒléments de physiologie:

And Diderot comes back to the same idea in his Pensées sur l’interprétation de la nature, when he writes: “ne croirait-on pas volontiers qu’il n’y a jamais eu qu’un premier animal prototype de tous les animaux dont la nature n’a fait qu’allonger, raccourcir, transformer, multiplier, oblitérer certains organes?”.^[37] A final remark that is worth noting on this subject occurs also in the passage from Eléments de physiologie already quoted, where Diderot writes:

However, little Diderot wanted in fact to assimilate certain humans to animals, it is clear that this type of thought, which abolishes the strict distinction between humans and animals and even looks for an intermediate being forming the bridge between the two, could encourage such a conclusion.^[39] The direction in which such ideas could be developed can be seen in other writers who were not at all materialists, such as Rousselet de Surgy, whose picture of the Africans as inferior beings concluded with the remark: “On serait tenté de croire, d’après ce portrait, que les Négres forment une race de créatures qui est la gradation par laquelle la nature semble monter, des Orang-Outangs, des Pongos, à l’homme”,^[40] a sentence quoted by the author of a “Lettre d’un Américain à l’auteur des Ephémérides du citoyen sur l’esclavage des nègres”, in defence of slavery (a letter which was only published by the Physiocratic Ephémérides du citoyen in order to provide the excuse for a condemnation of slavery).^[41] More virulent versions of the idea can be seen in Edward Long, spokesman for the West India Lobby, who developed the parallels between Blacks and orang-outangs (from an anti-materialistic standpoint)^[42] or Charles White’s Account of the Regular Gradation in Man (1799), whose arguments are based on differences in skulls and skeletons, whichlead him to deny the effect of climate and to affirm the original existence of separate races on a clear hierarchical scale of intelligence and “active powers”. In the same period Virey insisted on the closeness of certain apes to what he called the most deformed of human races. He concludes in favour of polygenesis, insisting, “qu’il existe en un mot dans le genre humain des différences radicales, constantes, indélébiles, bien plus profondes enfin que de simples variétés superficielles, qui seraient tout au plus individuelles”.^[43]

12. These writers were, it is true, not materialists, although Virey’s position was somewhat paradoxical, for while proclaiming himself an enemy of materialistic ideas and a defender of a vital force distinct from matter, and while affirming his belief in a divine creator, he clearly separates the scientific from the religious sphere; he affirms that natural history alone can enable us to understand humans, and natural history is based “avec la physiologie, sur l’étude de notre organisation”.^[44] It is precisely this physical determinism characterising materialistic thinking, and influencing scientific thought even among those who rejected its religious implications, which could have particularly far-reaching consequences concerning racialclassification when linked to the abolition of the distinction between humans and animals. Here again, the case of Diderot is interesting, for despite the remarks I have quoted concerning his hostility to forms of classification which introduced artificial distinctions, he seems to have been very much interested in the question of human varieties and the reasons for them. As I have already mentioned, he wrote the Encyclopédie article Humaine, espèce which is in fact a summary of Buffon’s book on humans andwhich therefore treats mankind as divided into more or less homogeneous groups sharing common characteristics, even if he affirms that these varieties could disappear if all humans were subject to the same determining causes. There is a clear hierarchy of varieties, from the most perfect races in the temperate zones to the “ugly” peoples of the North, who are all said to be “grossiers, superstitieux, et stupides”.^[45] The problem raised here concerns their supposed stupidity; for a materialist like Diderot, human intelligence is determined by physical organisation and in particular by the brain, and he was permanently fascinated by the question of the link between external appearance and intellectual capacities and character, which was why he was so interested in Camper’s physiognomy.

13. The argument concerning the determination of intellectual characteristics and capacity by bodily structure had already been particularly developed by La Mettrie, whose aim was to demonstrate that there is no immortal soul and that thought is produced by a particular organistion of matter in the brain.^[46] Thus he concludes, in line with eighteenth-century “Spinozism”, that humans are totaly determined by this physical organisation. He was not of course the first to affirm this, as there are developments in several anti-religious works of the early Eighteenth Century which show the dependence of intellectual faculties on the physical state, in order to cast doubt on the existence of an immaterial soul.^[47] If there is no immortal soul independent of the material body, and if the brain, a material organ, produces thought, then it is clear that the human being’s intellect, wishes and desires are the result of the physical workings of the body and they are not free to act against the promptings of their physical machine. Their will is determined by the physical organism and they are incapable of resisting the desires dictated by it. They are also the product of their circumstances and experiences, but in the last resort it is the physical “machine” which predominates. Thus, while education can have an effect, it is only temporary. As La Mettrie writes in his Anti-Sénèque:

14. Of course, La Mettrie, as a doctor, was solely interested in the individual and not in human groups, and was concerned in particular to show that individuals could not stop themselves from indulging in anti-social acts. But his arguments did imply, as he indicated in his Discours préliminaire, that only certain individuals with favoured organisms could attain not only moral integrity but also a certain intellectual capacity. The same conclusion is found in d’Holbach’s Système de la nature, which affirms the inequality of different individuals’ intellectual faculties as a result of a variety of mainly physical factors, both internal and external.^[49] Such arguments could be extended from individuals to human groups and the link between materialism and claims concerning the intellectual inferiority of particular races are undeniable, although not of course inevitable. I now want to discuss briefly how the question presented itself in the late Eighteenth Century, and here the case of Diderot is again most interesting, particularly his debate with fellow materialist Helvétius. C.-A. Helvétius was interested in the external factors determining human behaviour; for him, all humans were born with the same capacities, intellectual and moral in particular. The differences between them were accounted for by education, and the differences between peoples essentially by the type of government. Diderot’s debate with Helvétius, in the form of annotations, firstly to De l’esprit in 1758 and then at much greater length to the posthumously published De l’homme (1773-74), took the form of questions on the one hand about the nature of matter and the seat of sensitivity and intelligence, but on the other, more relevant to our present purpose, about the relative role of organisation, climate and education in determining human behaviour and intelligence. Already in his remarks on De l’Esprit, Diderot pointed out, against Helvétius, that a “légère altération dans le cerveau réduit l’homme de génie dans l’état d’imbécillité”; and he went on:

A similar remark is made in his discussion of De l’homme, where he continues:

15. When discussing nations rather than individuals, Diderot’s criticism of Helvétius tends to emphasize the influence of climate and to minimize that of government, pointing out that the same government has a different effect on minds in different climates.^[52] It seems to me significant that he follows this with the examples of cretins found in what he calls “the country of goitres”, which leads him to write, in a remark reminiscent of La Mettrie, “C’est qu’il est bien difficile de faire de la bonne métaphysique et de la bonne morale sans être anatomiste, naturaliste, physiologiste et médecin”.^[53] It is clear from this that for Diderot, physical causes, both external (climate) and internal (organisation) play a role in determining humans’ capacities. When dealing with individuals, their particular organisation is more important, but when it comes to nations, climate can seen to be more relevant. The difference we have seen before – between accidental (e.g. climatic) influences and innate internal influences, when discussing racial classification – is here if minor importance, as the point is not to show that differences are permanent, but that their causes are essentially physical rather than moral. Thus, while admitting that great men can be found in any nation, Diderot adds, “Quant à la diversité seule des climats, je croirais volontiers qu’il en est des esprits, ainsi que de certains fruits, bons partout, mais excellents dans certaine contrée”.^[54] The inequality of intelligence between different peoples in different regions seems thus evident. There is also an interesting remark to be found in Le Rêve de d’Alembert where Diderot, to emphasize that everything in nature is in permanent flux and that species are in permanenent evolution, puts in the mouth of the dreaming d’Alembert the following reflection:

16. This description bears a striking resemblance to the beginning of the article Humaine, espèce, describing the same far Northern peoples who, scarcely human and perhaps in the process of degenerating to the condition of animals, seem to be both physically and intellectually inferior. From this I think we can deduce that for Diderot here, external differences, due to the climate, correspond to internal differences in organisation, perhaps also due to the climate, which determine the intellectual faculties of a particular human group and set them apart from other groups, although these differences are not necessarily permanent and fixed. Thus his declaration in one of the fragments destined for the Histoire des Deux Indes, “il y a entre les hommes une inégalité à laquelle rien ne peut remédier”,^[56] seems to apply to groups as well as individuals and, as J. Proust has pointed out in connection with the article Humaine, espèce, Diderot seems to be accepting the idea of an “inégalité intellectuelle, qui existe entre les races” as well as between individuals.^[57]
But it was clear that this represented a problem for Diderot, as his aim, particularly in the passages he added to Histoire des Deux Indes against slavery, was rather to defend the unity of the human race, considered to be vital by the abolitionists as we have seen. Indeed, what interested him in general was the unity of nature rather than a classification and rigidification of its diversity, and he refused the idea that anything in nature could be fixed and unchanging. This, I think, prevented him from going down the road taken by many contemporaries in their reflections on racial difference. He did not develop his ideas in the direction of a hierarchical classification, preferring to come back to the question of the differences in government and organisation of different people, in other words of “savages” and “civilised peoples” and thus to history rather than physiology in this particular connection. In those discussions, he does not seem to want to make a connection between these two ways of classifying different peoples (by race or by the state of society). Similarly, d’Holbach was concerned with the way governments oppress people and inculcate false notions, rather than with innate differences between peoples.

17. Nevertheless this discussion, and the evident temptation to extend a materialistic conception of humans in this direction, indicate that there could be a connection between materialistic thought and racial classification, particularly evident in skull measurements as a means of classification. Thus Bory de Saint-Vincent, the polygenecist author of a particularly developed system of racial classification at the beginning of the Nineteenth Century, was a materialist.^[58] Likewise the distinguished doctor William Lawrence – who defended a monistic conception of human beings based on what he called “the electro-chemical doctrine of life” similar to J. Priestley’s, and was widely attacked for what were seen as his irreligious or “sceptical” ideas influenced by French physiology – drew conclusions from this materialism concerning the differences between races; he wrote in his Lectures on Comparative Anatomy, Physiology, Zoology, and the Natural History of Man (1817), which was dedicated to Blumenbach and adopted a monogenistic viewpoint:

Similarly, it is noticeable that the group of militantly anticlerical radicals and anthropologists who in France in the 1860s emphasized the inequality of the races, although defending Darwinian ideas and rejecting polygenecism, looked back to the eighteenth-century materialists as precursors of their ideas. One of them, Charles Letourneau, quoted Diderot’s criticism of Helvétius’s emphasis on education in order to support his affirmation concerning the intellectual inequality of humans and the existence of inferior and superior races.^[60] Here of course, Diderot’s hesitations and his refusal of fixed, unchanging racial differences, are ignored, in a very different ideological context.

18. This does not of course mean that there is a necessary correlation between materialism and a belief in racial inequality (there are several examples to prove the contrary as we have already seen), simply that the development of “scientific” systems of racial classification in the later Eighteenth Century which postulated a hierarchy between the races could to some extent be encouraged by the spread of materialistic ideas about the production of thought by the brain and physical determinism. These ideas influenced even some of those who did not espouse a materialistic position, to the extent that they distinguished sharply the spheres of science and religion and, after affirming their belief in God and an immortal soul, proceeded to discuss humans in purely material terms. What is particularly interesting here is the fact that this link between materialism and a belief in racial inequality or even polygenecism was part of the attack by certain abolitionists (most of whom were Quakers or Evangelicals). Thus the Reverend James Ramsay, who specifically defends the Biblical account of the common origin of all mankind against the scepticism of modern philosophers and the paradoxes of infidels, attacking Hume and Kames and their polygenetical arguments (not surprisingly in a work whose aim is to show the possibility and the need for conversion of the slaves and their education in Christian principles), particularly attacks the materialists’ theses; he insists that thought is incompatible with matter and refutes the theories of those who claim that man is nothing but organised matter, declaring that Locke would never have allowed himself to indulge in what he calls “that wild conjecture” concerning the possibility that God might have superadded the power of thinking to matter if he had foreseen the consequences that would be drawn from this conjecture by the materialists.^[61] Thus Ramsay denies that intelligence is in direct proportion to the size of the brain. But, while seeming to admit that Africans’ skulls are smaller than Europeans’, he claims that this is simply accidental and the result of particular circumstances, for he supposes that this size could increase over several generations due to civilisation, which would bring better food and a less harsh way of life. He writes,

19. He explains that this would be the case due to the better situation of women, their better food and so on, which would allow their babies’ brains to develop correctly in the womb and thus be as well-developed as those of “civilised” peoples.^[63] Ramsay’s position here seems somewhat paradoxical, for while condemning the materialists’ position concerning the correlation between brain size and intelligence, he takes the hypothesis seriously enough to try to demonstrate that brain size is not innate but the result of environmental conditions. His main argument also could have unforeseen implications, as he wants to show that with better treatment in the West Indies, the Africans could improve physically and intellectually and would thus be ready for Christianity. In a way, therefore, their forced removal to New World slavery can be beneficial to them. His general position, though, is that religion coincides with humanitarian arguments in favour of the Africans and against slavery. Or, as the Reverend Stanhop Smith wrote in the conclusion to his work,

Smith provides us with an example of the fact, pointed out by historians, that a particular interest of the American debate on the African’s origin and characteristics in this period was its bearing on the credibility of revealed religion.^[65] One could no doubt extend this remark to Britain at least.

20. In France, the abolitionist who went furthest in this direction was the abbé Grégoire, for whom the equality of all mankind was based on religious teaching and who rejected attempts at racial classification, despite his respect for certain anthropologists like Blumenbach (whom he visited and quoted approvingly on the subject of the unity of the human race).^[66] He insists on the difficulties inherent in the attempt to correlate brain size to intelligence and here he particularly criticizes Gall’s craniology, which he presents as a development of Camper’s theories concerning the facial angle. According to him, Gall “veut fonder sur la structure du crâne la prétendue infériorité morale des nègres”.^[67] Gall’s phrenology, although not openly materialistic (he rejected the label), is closely connected to materialistic thinking to the extent that he explained mental phenomena by the brain’s configuration. And for Grégoire it is clear that the enemy is to be found in the camp of the irreligious and in particular the materialists. He declares this openly in an important passage in La littérature des Nègres:

Grégoire is thus making a clear connection between systems of racial classification which imply a racial hierarchy, polygenesis, irreligion in general and materialism in particular, and defence of slavery and the colonial system (for basely pecuniary motives).^[69] Although, as is clear from the examples I have given above, his position is biassed and untenable, it is significant; he reminds us that the question of racial classification in the late Eighteenth and early Nineteenth Centuries was at the intersection of a complex system of ideas and arguments with wide-reaching ramifications, and that its ideological implications cannot be ignored. The unresolved aspects of the debate were to have important consequences in the century to come, when science and religion seemed to come down on opposite sides of the fence, despite the influence of James Cowles Prichard’s tenacious attempts to reconcile the Biblical account with science. In the nineteenth-century physical anthropologists’ appeal to science against religious orthodoxy and “sentiment” when affirming the inherent inequality of races and polygenecism, we find echoes – and a drastic simplification – of the eighteenth-century debate.