That slavery may have its bad aspects but it has been the engine of good, it has been the engine of empires, the engine of wealth, the engine of greatness.

奴隶制本身也有不好的方面,但是它曾是一切善行的起源,帝国崛起的推动力,是一切财富的来源,伟大事物的起源

耶鲁公开课 - 美国内战与重建课程节选