Historians use logic, too. Logic does not belong exclusively to the domain of mathematicians, physicists, and philosophers. The only difference is that we deal primarily with concepts, rather than numbers. But for students who are particularly adept at understanding mathematical concepts and proofs, I am thinking of writing this up on the chalkboard as a demonstration:
Premise 1: The system of slavery, as practiced in the United States during the antebellum era, was dependent upon - and enforced by - brutal violence and in some cases, torture. We know this from primary sources such as the Narrative of Henry Watson and the work of Edward Baptist, as well as many other historians.
Premise 2: We also know that slavery was fundamental to the development of modern capitalism, as demonstrated by the development of the Cotton Kingdom, westward expansion, and the development of modern insurance companies and banks.
Conclusion: Therefore, in the US context, the development of capitalism was not always free and liberating, but was quite often linked inextricably with violence, torture, and brutality.
This is far from an original insight, but I wanted to arrange it in a way that made sense, both to myself and my students. Given that the College Board, which administers the AP US History test, has caved to ill-informed and reactionary political pressures in recently restructuring its narrative to emphasize more "positive" aspects of US history, it is even more incumbent upon college history professors to develop these sorts of ideas in the classroom.