We thought there were different species of man, so we made slavery totally cool
Slavery has been a thing since the earliest days of man, and it’s sort of like one of those Magic Eye posters. Every time you look at it a little bit differently, you see something that’s a slightly different kind of awful. Those who believed in it and practiced it needed to keep finding ways to convince themselves it was all right, and in the 19th century, one of those ways was the idea of polygenism.
According to Pittsburg State University’s Robert A. Smith, it was Dr. Charles Caldwell who popularized the idea that humanity had several different origin points. He was writing in the 1830s when he came up with the theory of different races originating in different places, and by the time JC Nott and George Gliddon wrote Types of Man, that turned into the idea there were different species within mankind. Nott went as far as talking about “hybrid” offspring, saying these people were occasionally fertile and proposed nature had come up a system that “permitted the gradual extinction of hybrid races.” So he took a crack at offending pretty much everyone and also reinterpreted history through an unthinkably racist lens — certain people loved it.
He wasn’t the only one saying it, either. Louis Agassiz, a Harvard professor, wrote about his observations on how different races were, and polygenism successfully went on to be the rallying cry for anyone looking for a handy excuse to justify slavery.