What is the horrible pit? Why does Douglass envy someone's stupidity?

Douglass also became fully aware of the reality of slavery; he wrote "[Literacy] had given me a view of my wretched condition, without the remedy. It opened my eyes to the horrible pit, but to no ladder upon which to get out. In moments of agony, I envied my fellow-slaves for their stupidity" (36). Ignorance was thus a way for slaveholders to keep their slaves manageable, happy, placid, and content. Once a slave moved beyond such darkness into a world filled with understanding, he was only able to do what Douglass eventually did - attempt to escape from his bonds.