Credit: Special Collections and Rare Books, University of Minnesota Libraries
Expanding on the work of Carolus Linnaeus, German professor of medicine Johann Friedrich Blumenbach introduced one of the race-based classifications in On the Natural Variety of Mankind. In the second edition Blumenbach changed his original geographically based four-race arrangement to a five-group one that emphasized physical morphology (the study of the form of an organism). Blumenbach’s five categories were: Caucasian, the white race; Mongolian, the yellow race; Malayan, the brown race; Ethiopian, the black race; and American, the red race. Although he retained geographical names for his categories, the change marked a shift from geography to physical appearance.
The age of Enlightenment provided the backdrop for eighteenth century European theories about human difference. Exploration of Africa, Asia and the Americas brought Europeans in contact with people whom they found quite different. The rise of prominent Enlightenment thinkers including Voltaire, Jean-Jacques Rousseau, Immanuel Kant and David Hume, among others-greatly influenced European ideas about economics, government and science. The framework of Enlightenment philosophy in Europe was the belief that reason and rationality provided an authoritative system of ethics, aesthetic values and knowledge.