What we dream up must be lived down, I think.

Merrill’s line turns the usual romance of “dreaming up” ideas on its head: imagination is not cost-free, and what we invent—plans, fantasies, self-mythologies, even works of art—creates obligations and consequences that must be borne in ordinary life. “Lived down” suggests embarrassment, regret, or the slow work of reconciling oneself to what one has said, desired, or made. The qualifying “I think” adds a characteristically wry, self-aware tone, as if the speaker recognizes both the inevitability of dreaming and the humbling aftermath. The aphorism captures a tension central to much twentieth-century writing: the gap between inner invention and the stubborn, public, temporal world that follows.