F. Scott Fitzgerald on Holding Opposing Ideas in the Mind"The Crack-Up" (February, 1936) in The Crack-Up, ed. Edmund Wilson (New Directions: Feb 27, 2009), pp. 69-70.
Let me make a general observation — the test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function. One should, for example, be able to see that things are hopeless and yet be determined to make them otherwise. … I must hold in balance the sense of the futility of effort and the sense of the necessity to struggle; the conviction of the inevitability of failure and still the determination to “succeed” — and, more than these, the contradiction between the dead hand of the past and the high intentions for the future.