The Age of was a period of time during the 18th century (1700s) in Europe where political, scientific, social, and philosophical ideas flourished and underwent radical change. Enlightenment thinkers traditional hierarchical structures and authority; they argued that humans could society through rational thinking.

Like John Locke, most Enlightenment thinkers believed that all humans are entitled to certain basic rights that they called . In time, these ideas spread and shaped the way ordinary people viewed the world. Some began to say that if societies are human inventions, rather than ordained by God, then have the right to alter or even an oppressive government with one more to their liking.

But the emphasis on human equality presented Enlightenment leaders with a dilemma. Historian Ira Berlin explains:

“After the Declaration of the Rights of Man [and] the Declaration of Independence, the presumption is that all men are created equal. Equality is the point. And what then has to be explained for the very first time in world history is inequality, and why inequality exists. In other words, if all men are created equal, why are some men and women still slaves?”

Although the great thinkers of the Enlightenment stressed the of humankind, the belief that humanity is divided into separate and unequal races continued to develop during those same years. Less than ten years after writing the Declaration of Independence, Thomas , a slaveholder himself, wrote: