History shows that there is nothing so easy to enslave and nothing so hard to emancipate as ignorance, hence it becomes the double enemy of civilization. By its servility it is the prey of tyranny, and by its credulity it is the foe of enlightenment.

Washburn frames ignorance as civilization’s “double enemy” because it makes people vulnerable in two directions at once: politically, ignorance is “easy to enslave,” supplying tyranny with compliant subjects; intellectually, it is “hard to emancipate,” because credulity resists correction and clings to comforting falsehoods. The sentence balances two paired contrasts—servility/tyranny and credulity/enlightenment—to argue that oppression and misinformation reinforce each other. The quote thus reads as a civic warning: education is not merely personal improvement but a public defense against authoritarian control and against the spread of error that blocks reform.