The essential Thomas Sowell lectures
Thomas Sowell is an economist and sociologist specializing in economic issues of race and culture.

"The Importance of Cultural Diversity in America and the World"
https://www.youtube.com/watch?v=ZcYsQM_Mt9Q

"The Quest for Cosmic Justice"
https://www.youtube.com/watch?v=xkDMVdEci4Q

"The effect of preferential policies" (about affirmative action)
https://www.youtube.com/watch?v=GC2l24xOJzA
https://www.youtube.com/watch?v=T2hPQ86lGV0

Thomas Sowell with William Buckley Jr.
https://www.youtube.com/watch?v=Y021WAdUlW8