What did W.E.B. Du Bois mean when he wrote of second-sight?

Activist, historian, sociologist, and writer W.E.B. Du Bois wrote, in the first chapter of The Souls of Black Folk, that the American Negro is

gifted with second-sight in this American world, — a world which . . . only lets him see himself through the revelation of the other world. It is a peculiar sensation, this double-consciousness, this sense of always looking at one's self through the eyes of others, of measuring one's soul by the tape of a world that looks on in amused contempt and pity. One ever feels his two-ness, — an American, a Negro; two souls, two thoughts, two unreconciled strivings; two warring ideals in one dark body, whose dogged strength alone keeps it from being torn asunder.

In Du Bois' time, Blacks found themselves in the paradoxical situation of both being American and not being accepted in American society, creating a conflict between the compulsion to find one's place in American society and the desire not to lose one's African-ness. As Du Bois states, "the history of the American Negro is the history of this strife."

Du Bois' second-sight refers to African Americans' ability, even need, to see themselves not only as they are, but also as the rest of (White) America sees them.