At the beginning of the transatlantic slave trade, most Europeans grouped Africans into the despised categories of pagan heathens or Muslim infidels. As Europeans turned to Africa for new sources of slaves, they drew on beliefs about Africans’ primitiveness and barbarity to defend slavery.

Over time, the institution of slavery fostered a new level of racial inequality. Africans gradually became seen as utterly distinct from and wholly inferior to Europeans. In a transition from rather vague assumptions about Africans’ non-Christian religious beliefs and general lack of civilization, Europeans developed increasingly rigid ideas of racial superiority and inferiority to safeguard the growing profits gained from plantation slavery. Black skin became equated with slavery itself as Europeans at home and in the colonies convinced themselves that blacks were destined by God to serve them as slaves in perpetuity. Support for this belief went back to the Greek philosopher Aristotle’s argument that some people are naturally destined for slavery and to biblical associations between darkness and sin.

After 1700 the emergence of new methods of observing and describing nature led to the use of science to define race. Although previously the term referred to a nation or an ethnic group, henceforth “race” would be used to describe supposedly biologically distinct groups of people whose physical differences produced differences in culture, character, and intelligence. Biblical justifications for inequality thereby gave way to allegedly scientific ones (see “Science for the Masses” in Chapter 24).