The biologization of race was preceded by significant extension of its older genealogical referents as some writers extrapolated the term to label extensive populations. They included the French physician and Asian traveller François Bernier (1620-1688), the German mathematician and philosopher Gottfried Wilhelm Leibniz (1646-1716), the French mathematician, astronomer, and biologist Pierre-Louis Moreau de Maupertuis (1698-1759), the Anglo-Irish writer, poet, and physician Oliver Goldsmith (1730?-1774), and the French naturalist Georges-Louis Leclerc, comte de Buffon (1707-1788),^[8] whose expanded use of the term 'Lapp race' (Sami) provoked some disapproval.^[9] In these extended usages, race was usually a concrete noun more or less interchangeable with 'tribe', 'nation', 'people', 'variety', 'class', 'kind', or 'species'. Leibniz used the word rarely but defined it relationally as 'generational series', 'genealogy'.^[10] Race was applied to Oceania in this fluid sense by the French littérateur Charles de Brosses (1709-1777), a friend of Buffon, and by the German naturalists Johann Reinhold Forster (1729-1798) and his son Georg (1754-1794), who sailed with James Cook (1728-1779) on his second Oceanic voyage of 1772‑75.^[11]

As subdivisions of a single human species, varieties or races were distinguished by physical criteria, especially skin colour, in addition to language, religion, customs, and supposed level of 'civility'. In practice, the venerable, widely-held tenet that all people shared a common origin and were essentially alike was in serious tension with pervasive distaste for non-whites and non-Christians. Following the overseas expansion of Europe and growing involvement in the west African slave trade from the mid-fifteenth century, a set of purportedly 'Negro' characteristics had become Europe's negative standard for the description and comparison of human beings. Nonetheless, prevailing Christian or neoclassical cosmologies generally ascribed both physical appearance and degree of civilized development to the transient effects of climate, other external conditions, history, or way of life, more than to heredity, and in principle espoused a universal potential for salvation or progress towards the civilized state.^[12]

The changed and charged import of the concept race in the early nineteenth century is commonly seen by historians of ideas as a by-product of the abstract taxonomic method instituted from the 1730s by the Swedish botanist Carl Linnaeus (von Linné) (1707-1778). By this argument, Linnaeus 'blurred' the frontier separating man from animals by classifying both within the same 'natural system' and thereby 'brought to light new differences between men'.^[13] In the tenth edition of Systema Naturae (1758:5-24), he classed all known human geographical varieties within the single species Homo sapiens but included Homo, 'Man', within the 'Animal Kingdom' as the first genus in the mammalian order of primates, alongside Simia, 'Ape'. This failure to isolate man from the rest of creation and from the anthropoid apes in particular threatened the dogma of the singularity of mankind and outraged conventional opinions. In the monumental Histoire naturelle, générale et particulière (1749-89), Linnaeus's great rival Buffon criticized abstraction and classification alike: he transformed the abstract category espèce, 'species', by insisting on its 'real existence' and material historical continuity as a 'constant succession of similar individuals who reproduce themselves'; and he refused to position man in formal taxonomic relationship with animals. But by encompassing humanity within 'natural history', he eventually naturalized man as a physical species distinguished from animals only by the fragile criteria of speech and reason.^[14]

Tzvetan Todorov (1989:126) damned Buffon for espousing 'the racialist theory in its entirety' but the charge is scarcely applicable to the haphazard, ambiguous use of race in Buffon's long essay on 'Varieties in the human species' (1749, III:371-530). He first systematically applied race to human beings in a much later Supplément to the Histoire naturelle, but with the broad connotation of 'resemblance' rather than direct filiation. He justified his earlier use of the phrase 'the Lapp race' by differentiating 'the word race in the most extended sense' from its 'narrow' (genealogical) meaning, synonymous with nation. An extreme climate had produced such 'resemblance' between all people living north of the Arctic Circle, whatever their 'first origin', that they had become 'a single identical race' though they were 'not of the same nation'. Juxtaposing two major signifieds of the French term espèce ('kind'/'species') and identifying race with the vaguer common sense, he concluded that these polar people were 'a single, similar kind of men [espèce d'hommes], that is, a single race different from all the others in the human species [espèce humaine]'.^[15] The apparent biological modernity of this formulation is deceptive since Buffon continued to assert that the 'great differences between men depend on the diversity of climate'. In this conception, the variétés, races, or espèces d'hommes of the single espèce humaine remained flexible, theoretically reversible products of climatic variety and other external influences and were neither innately organic nor immutable.^[16]

Though Maupertuis (1745:153-60) rarely used the word race in his short biological treatise Vénus physique, he proposed a prescient epigenetic theory of reproduction which made human physical diversity primarily the product of internal hereditary processes rather than the external 'influence' of climate and diet. By contrast, there is no hint of a biological account of race formation in Buffon's original essay which attributes the characteristic physical differences 'of the various peoples' to the impact of climate, food, and lifestyle but does not seek to explain why. From 1753, Buffon gradually enunciated a theory of the organic alteration of species through degeneration triggered by external conditions but he only applied these emerging ideas to human beings in the mid-1760s, when he argued that the quality of food channels 'the influence of the land' to alter man's 'internal form'. Perpetuated 'by generation' — but reversible in principle in a restored favourable environment — such organic changes 'became the general and constant characters in which we recognize the different races and even nations which compose the human genus'.^[17] Still later, Buffon (1778:248) qualified his thesis of human degeneration with the proposition that the process of becoming civilized could itself enable and sustain organic improvement in man through better nutrition and 'plentiful reproduction'.

In Britain, Goldsmith (1774, II:212-42) avowedly synthesized Linnaeus and Buffon by distilling a formal classification of mankind into 'six distinct varieties', labelled geographically as the 'polar' race, 'the Tartar race', 'the southern Asiatics', 'the Negroes of Africa', 'the inhabitants of America', and 'the Europeans'. This explicit identification of discrete racial 'classes' flew in the face of Buffon's refusal to indulge in human taxonomy but in most respects Goldsmith's propositions were slavishly, if simplistically Buffonian. He differentiated man mainly on the basis of the 'tincture of his skin' and explained these differences as 'degeneracy' from a 'beautiful' white original caused by 'varieties of climate, of nourishment, and custom'. And, like Buffon, he concluded that such 'accidental deformities' would probably disappear in the long run with a 'kinder climate, better nourishment, or more civilized manners'.