This Juneteenth — the day celebrating the end of slavery in the United States — take a moment to think about what it means to be free.

Harvard sociologist Orlando Patterson provocatively argues that without the notion of slavery the concept of freedom cannot fully exist. In his lecture, “Free at last: How slavery begat freedom,” he explains that freedom is a concept unique to the west. Without our ugly history of slavery, in Patterson’s telling, we could not cherish the gift of liberty as we should.

This lecture was originally delivered at AEI in November 1993.

Listen to the full lecture here.