During the Age of Enlightenment (an era from the 1650s to the 1780s), concepts of monogenism and polygenism became popular, though they would only be systematized epistemologically during the 19th century. Monogenism contends that all races have a single origin, while polygenism is the idea that each race has a separate origin. Until the 18th century, the words "race" and "species" were interchangeable.
Robert Boyle vs. Henri de Boulainvilliers
An early scientist who studied race was Robert Boyle (1627–1691), an Anglo-Irish natural philosopher, chemist, physicist, and inventor. Boyle believed in what today is called 'monogenism', that is, that all races, no matter how diverse, came from the same source, Adam and Eve. He studied reported stories of parents' giving birth to different coloured albinos, so he concluded that Adam and Eve were originally white and that whites could give birth to different coloured races. Theories of Robert Hooke and Isaac Newton about color and light via optical dispersion in physics were also extended by Robert Boyle into discourses of polygenesis, speculating that maybe these differences were due to "seminal impressions". However, Boyle's writings mention that at his time, for "European Eyes", beauty was not measured so much in colour, but in "stature, comely symmetry of the parts of the body, and good features in the face". Various members of the scientific community rejected his views and described them as "disturbing" or "amusing".
On the other hand, historian Henri de Boulainvilliers (1658–1722) divided the French as two races: (i) the aristocratic "French race" descended from the invader Germanic Franks, and (ii) the indigenous Gallo-Roman race (the political Third Estate populace). The Frankish aristocracy dominated the Gauls by innate right of conquest.
In his time, Henri de Boulainvilliers, a believer in the "right of conquest", did not understand "race" as biologically immutable, but as a contemporary (racist) cultural construct. His racialist account of French history was not entirely mythical: despite "supporting" hagiographies and epic poetry, such as The Song of Roland (La Chanson de Roland, c. 12th century), he sought scientific legitimation by basing his racialist distinction on the historical existence of genetically and linguistically distinguished Germanic and Latin-speaking peoples in France. His theoretic racialism was distinct from the biologic facts manipulated in 19th-century scientific racism. (cf. Cultural relativism)
The Scottish lawyer Henry Home, Lord Kames (1696–1782) was a polygenist: he believed God had created different races on Earth in separate regions. In his 1734 book Sketches on the History of Man, Home claimed that the environment, climate, or state of society could not account for racial differences, so the races must have come from distinct, separate stocks.
, or Patagonian giants, from Voyage au pole sud et dans l'Océanie
(Voyage to the South Pole, and in Oceania
), by Jules Dumont d'Urville
Carl Linnaeus (1707–1778), the Swedish physician, botanist, and zoologist, modified the established taxonomic bases of binomial nomenclature for fauna and flora, and was a pioneer researcher in biologically defining human race. In Systema Naturae (1767), he labeled five "varieties" of human species.
Each one was described as possessing the following physiognomic characteristics "varying by culture and place":
- The Americanus: red, choleraic, righteous; black, straight, thick hair; stubborn, zealous, free; painting himself with red lines, and regulated by customs.
- The Europeanus: white, sanguine, browny; with abundant, long hair; blue eyes; gentle, acute, inventive; covered with close vestments; and governed by laws.
- The Asiaticus: yellow, melancholic, stiff; black hair, dark eyes; severe, haughty, greedy; covered with loose clothing; and ruled by opinions.
- The Afer or Africanus: black, phlegmatic, relaxed; black, frizzled hair; silky skin, flat nose, tumid lips; females without shame; mammary glands give milk abundantly; crafty, sly, lazy, cunning, lustful, careless; anoints himself with grease; and governed by caprice.
- The Monstrosus were mythologic humans which didn't appear in the first editions of Systema Naturae. The sub-species included the "four-footed, mute, hairy" Homo feralis (Feral man); the animal-reared Juvenis lupinus hessensis (Hessian wolf boy), the Juvenis hannoveranus (Hannoverian boy), the Puella campanica (Wild-girl of Champagne), and the agile, but faint-hearted Homo monstrosus (Monstrous man): the Patagonian giant, the Dwarf of the Alps, and the monorchid Khoikhoi (Hottentot). In Amoenitates academicae (1763), Linnaeus presented the mythologic Homo anthropomorpha (Anthropomorphic man), humanoid creatures, such as the troglodyte, the satyr, the hydra, and the phoenix, incorrectly identified as simian creatures.
There are disagreements about what was the basis for Linnaeus' human taxa. On the one hand, the harshest critics say that the classification not only was ethnocentric but seemed to be based upon skin-color. On the other hand, Quintyn (2010) points out that some authors believe the classification was based upon geographical distribution, being cartographically based, and not hierarchical. Paleontologist Stephen Jay Gould (1994) argues that the taxa was "not in the ranked order favored by most Europeans in the racist tradition", and that Linnaeus' division was influenced by the medical theory of humors which said that a person's temperament may be related to biological fluids. In the opinion of Kenneth A.R. Kennedy (1976), Linneus certainly considered his own culture better, but his motives for classification of human varieties were not race-centered. The Linnean Society of London has stated that in Linnaeus' view, "Europeans' superiority resides in "culture", and that the decisive factor in Linnaeus' taxa was "culture", not race. Thus, regarding this topic, they consider Linnaeus view as merely "eurocentric", arguing that Linnaeus never called for racist action, and did not use the word "race", which was only introduced later "by his French opponent Buffon". Scholar Stanley A. Rice agrees that Linnaeus' classification was not meant to "imply a hierarchy of humanness or superiority"; although modern critics see that his classification was obviously stereotyped, and erroneous for having included anthropological, non-biological features such as customs or traditions.
John Hunter (1728–1793), a Scottish surgeon, said that originally the Negroid race was white at birth. He thought that over time because of the sun, the people turned dark skinned, or "black". Hunter also said that blisters and burns would likely turn white on a Negro, which he believed was evidence that their ancestors were originally white.
Charles White (1728–1813), an English physician and surgeon, believed that races occupied different stations in the "Great Chain of Being", and he tried to scientifically prove that human races have distinct origins from each other. He believed that whites and Negroes were two different species. White was a believer in polygeny, the idea that different races had been created separately. His Account of the Regular Gradation in Man (1799) provided an empirical basis for this idea. White defended the theory of polygeny by rebutting French naturalist Georges-Louis Leclerc, Comte de Buffon's interfertility argument, which said that only the same species can interbreed. White pointed to species hybrids such as foxes, wolves, and jackals, which were separate groups that were still able to interbreed. For White, each race was a separate species, divinely created for its own geographical region.
Johann Friedrich Blumenbach
Buffon and Blumenbach
The French naturalist Georges-Louis Leclerc, Comte de Buffon (1707–1788) and the German anatomist Johann Blumenbach (1752–1840) were believers in monogenism, the concept that all races have a single origin. They also believed in the "degeneration theory" of racial origins. They both said that Adam and Eve were Caucasian and that other races came about by degeneration from environmental factors, such as the sun and poor dieting. They believed that the degeneration could be reversed if proper environmental control was taken, and that all contemporary forms of man could revert to the original Caucasian race.
They thought Negroid pigmentation arose because of the heat of the tropical sun. They suggested cold wind caused the tawny colour of the Eskimos. They thought the Chinese relatively fair skinned compared to the other Asian stocks because they kept mostly in towns and were protected from environmental factors. Buffon said that food and the mode of living could make races degenerate and differentiate them from the original Caucasian race. According to Blumenbach, there are five races, all belonging to a single species: Caucasian, Mongolian, Ethiopian, American, and Malay. Blumenbach said:
"I have allotted the first place to the Caucasian for the reasons given below which make me esteem it the primeval one."
Buffon believed humanity was only 6000 years old (the time since Adam). Many scientific racialists pointed out at the time that it would have been difficult for races to change so markedly in genotype and phenotype in such a short period of time. Believing in monogenism, Buffon thought that skin colour could change in a single lifetime, depending on the conditions of climate and diet.
Benjamin Rush (1745–1813), a Founding Father of the United States and a physician, proposed that being black was a hereditary skin disease, which he called "negroidism", and that it could be cured. Rush believed non-whites were really white underneath but they were stricken with a non-contagious form of leprosy which darkened their skin color. Rush drew the conclusion that "whites should not tyrannize over [blacks], for their disease should entitle them to a double portion of humanity. However, by the same token, whites should not intermarry with them, for this would tend to infect posterity with the 'disorder'... attempts must be made to cure the disease".
Christoph Meiners (1747–1810) was a German polygenist and believed that each race had a separate origin. Meiner studied the physical, mental and moral characteristics of each race, and built a race hierarchy based on his findings. Meiners split mankind into two divisions, which he labelled the "beautiful white race" and the "ugly black race". In Meiners's book The Outline of History of Mankind, he said that a main characteristic of race is either beauty or ugliness. He thought only the white race to be beautiful. He considered ugly races to be inferior, immoral and animal-like. He said that the dark, ugly peoples were distinct from the white, beautiful peoples by their "sad" lack of virtue and their "terrible vices". According to Meiners,
The more intelligent and noble people are by nature, the more adaptable, sensitive, delicate, and soft is their body; on the other hand, the less they possess the capacity and disposition towards virtue, the more they lack adaptability; and not only that, but the less sensitive are their bodies, the more can they tolerate extreme pain or the rapid alteration of heat and cold; when they are exposed to illnesses, the more rapid their recovery from wounds that would be fatal for more sensitive peoples, and the more they can partake of the worst and most indigestible foods ... without noticeable ill effects.
Meiners said the Negro felt less pain than any other race and lacked in emotions. Meiners wrote that the Negro had thick nerves and thus was not sensitive like the other races. He went as far as to say that the Negro has "no human, barely any animal, feeling". He described a story where a Negro was condemned to death by being burned alive. Halfway through the burning, the Negro asked to smoke a pipe and smoked it like nothing was happening while he continued to be burned alive. Meiners studied the anatomy of the Negro and came to the conclusion that Negroes have bigger teeth and jaws than any other race, as Negroes are all carnivores. Meiners claimed the skull of the Negro was larger but the brain of the Negro was smaller than any other race. Meiners claimed the Negro was the most unhealthy race on Earth because of its poor diet, mode of living and lack of morals.
Meiners also claimed the "Americans" were an inferior stock of people. He said they could not adapt to different climates, types of food, or modes of life, and that when exposed to such new conditions, they lapse into a "deadly melancholy".
Meiners studied the diet of the Americans and said they fed off any kind of "foul offal". He thought they consumed very much alcohol. He believed their skulls were so thick that the blades of Spanish swords shattered on them. Meiners also claimed the skin of an American is thicker than that of an ox.
Meiners wrote that the noblest race was the Celts. They were able to conquer various parts of the world, they were more sensitive to heat and cold, and their delicacy is shown by the way they are selective about what they eat. Meiners claimed that Slavs are an inferior race, "less sensitive and content with eating rough food". He described stories of Slavs allegedly eating poisonous fungi without coming to any harm. He claimed that their medical techniques were also backward: he used as an example their heating sick people in ovens, then making them roll in the snow.
In Meiners's large work entitled Researches on the Variations in Human Nature (1815), he studied also the sexology of each race. He claimed that the African Negroids have unduly strong and perverted sex drives, whilst only the white Europeans have it just right.
Thomas Jefferson (1743–1826) was an American politician, scientist, and slave owner. His contributions to scientific racism have been noted by many historians, scientists and scholars. According to an article published in the McGill Journal of Medicine: "One of the most influential pre-Darwinian racial theorists, Jefferson’s call for science to determine the obvious “inferiority” of African Americans is an extremely important stage in the evolution of scientific racism." The historian Paul Finkelman described Jefferson in The New York Times as follows: "A scientist, Jefferson nevertheless speculated that blackness might come “from the color of the blood” and concluded that blacks were “inferior to the whites in the endowments of body and mind.”" In his "Notes on the State of Virginia" Jefferson described black people as follows:
They seem to require less sleep. A black, after hard labor through the day, will be induced by the slightest amusements to sit up till midnight, or later, though knowing he must be out with the first dawn of the morning. They are at least as brave, and more adventuresome. But this may perhaps proceed from a want of forethought, which prevents their seeing a danger till it be present. When present, they do not go through it with more coolness or steadiness than the whites. They are more ardent after their female: but love seems with them to be more an eager desire, than a tender delicate mixture of sentiment and sensation. Their griefs are transient. Those numberless afflictions, which render it doubtful whether heaven has given life to us in mercy or in wrath, are less felt, and sooner forgotten with them. In general, their existence appears to participate more of sensation than reflection... Comparing them by their faculties of memory, reason, and imagination, it appears to me, that in memory they are equal to the whites; in reason much inferior, as I think one [black] could scarcely be found capable of tracing and comprehending the investigations of Euclid; and that in imagination they are dull, tasteless, and anomalous... I advance it therefore as a suspicion only, that the blacks, whether originally a distinct race, or made distinct by time and circumstances, are inferior to the whites in the endowments both of body and mind.
However, by 1791, Jefferson had to reassess his earlier suspicions of whether blacks were capable of intelligence when he was presented with a letter and almanac from Benjamin Banneker, an educated black mathematician. Delighted to have discovered scientific proof for the existence of black intelligence, Jefferson wrote to Banneker:
No body wishes more than I do to see such proofs as you exhibit, that nature has given to our black brethren, talents equal to those of the other colors of men, & that the appearance of a want of them is owing merely to the degraded condition of their existence both in Africa & America. I can add with truth that no body wishes more ardently to see a good system commenced for raising the condition both of their body & mind to what it ought to be, as fast as the imbecility of their present existence, and other circumstance which cannot be neglected, will admit. 
Samuel Stanhope Smith
Samuel Stanhope Smith (1751–1819) was an American Presbyterian Minister and author of Essay on the Causes of Variety of Complexion and Figure in the Human Species in 1787. Smith claimed that Negro pigmentation was nothing more than a huge freckle that covered the whole body as a result of an oversupply of bile, which was caused by tropical climates.
Racial studies by Georges Cuvier (1769–1832), the French naturalist and zoologist, influenced scientific polygenism and scientific racism. Cuvier believed there were three distinct races: the Caucasian (white), Mongolian (yellow) and the Ethiopian (black). He rated each for the beauty or ugliness of the skull and quality of their civilizations. Cuvier wrote about Caucasians: "The white race, with oval face, straight hair and nose, to which the civilised people of Europe belong and which appear to us the most beautiful of all, is also superior to others by its genius, courage and activity".
Regarding Negroes, Cuvier wrote:
The Negro race ... is marked by black complexion, crisped or woolly hair, compressed cranium and a flat nose. The projection of the lower parts of the face, and the thick lips, evidently approximate it to the monkey tribe: the hordes of which it consists have always remained in the most complete state of barbarism.
He thought Adam and Eve were Caucasian and hence the original race of mankind. The other two races arose by survivors' escaping in different directions after a major catastrophe hit the earth 5,000 years ago. He theorized that the survivors lived in complete isolation from each other and developed separately.
One of Cuvier's pupils, Friedrich Tiedemann, was one of the first to make a scientific contestation of racism. He argued based on craniometric and brain measurements taken by him from Europeans and black people from different parts of the world that the then-common European belief that Negroes have smaller brains, and are thus intellectually inferior, is scientifically unfounded and based merely on the prejudice of travellers and explorers.
Arthur Schopenhauer portrait
The German philosopher Arthur Schopenhauer (1788–1860) attributed civilizational primacy to the white races, who gained sensitivity and intelligence via the refinement caused by living in the rigorous Northern climate:
The highest civilization and culture, apart from the ancient Hindus and Egyptians, are found exclusively among the white races; and even with many dark peoples, the ruling caste, or race, is fairer in colour than the rest, and has, therefore, evidently immigrated, for example, the Brahmins, the Inca, and the rulers of the South Sea Islands. All this is due to the fact that necessity is the mother of invention, because those tribes that emigrated early to the north, and there gradually became white, had to develop all their intellectual powers, and invent and perfect all the arts in their struggle with need, want, and misery, which, in their many forms, were brought about by the climate. This they had to do in order to make up for the parsimony of nature, and out of it all came their high civilization.
Franz Ignaz Pruner
Franz Ignaz Pruner (1808–1882) was a medical doctor who studied the racial structure of Negroes in Egypt. In a book which he wrote in 1846 he claimed that Negro blood had a negative influence on the Egyptian moral character. He published a monograph on Negroes in 1861. He claimed that the main feature of the Negro's skeleton is prognathism, which he claimed was the Negro's relation to the ape. He also claimed that Negroes had very similar brains to apes and that Negroes have a shortened big toe, which is a characteristic connecting Negroes closely to apes.