Original sin is that thing about man which makes him capable of conceiving of his own perfection and incapable of achieving it.
Source: Obituary in Newsweek, 14 Jun 1972.
-- Reinhold Niebuhr, (Jun 21 1892-1971), US theologian, author; He pioneered the philosophy of Christian realism; wrote Nature and Destiny of Man, 1943; received Medal of Freedom, 1964.