Solomon Northrup and Frederick Douglass published two of the most widely-read and influential "slave narratives" in the antebellum period. Northrup's Twelve Years a Slave told his story, which included being kidnapped (he was a free man in New York) and sold into slavery in the Deep South. His account of his time in slavery is full of vivid descriptions of the horrors of slavery and its effects on the individuals who spent their lives as enslaved people. Northrup was forced into a number of jobs, including field hand, and actually served as an enslaved driver—he had to oversee the work of other enslaved people. The book's climactic scene—the brutal whipping of a young enslaved woman named Patsey—is a stark rebuke to anyone who argues that slavery is a "positive good," especially because Patsey's whipping is more or less a result of her sexual abuse at the hands of her owner, Epps. Nobody reading the book could seriously claim that these people experienced slavery as a positive good.
Frederick Douglass's Narrative is full of similar horrors of slavery. Unlike Northrup, Douglass grew up enslaved. One of his earliest memories, he writes, was witnessing the brutal whipping of his aunt, who was one of the people in charge of taking care of him after his mother was sold away. Douglass also points to the corrupting influence of slavery on everyone involved in the institution, including whites. He points to the example of Sophia Auld, the young wife of the man who purchased him as a young man. She attempted to teach Douglass to read, but after years as an enslaver she became as cruel as her husband. His story also emphasizes the disconnect between the professed Christianity of the enslavers and their cruelty to the people they enslaved; "[R]eligious slaveholders," he wrote, are the worst. "I have ever found them the meanest and basest, the most cruel and cowardly, of all others." This was in many ways a direct rebuke of the "positive good" defense of slavery, which argued that enslavers brought Christianity to people who presumably would not otherwise have been Christianized. In short, Douglass's account, like that of Northrup, firmly and convincingly contradicts the contemporary notion of slavery as a "positive good." It was, as both of these authors showed, an unmitigated evil.