Nietzsche suggests that even individuals who take themselves to bear an affirmative attitude toward life would be horrified by the thought of eternal recurrence (roughly, the idea that our lives will repeat endlessly in exactly the same fashion). But why? Why is it supposed to be more difficult to affirm recurring lives than to affirm a non-recurring, singular life? I argue that standard interpretations of eternal recurrence are unable to answer this question. I offer a new interpretation of eternal recurrence, (...) which attributes its difficulty to the conditional nature of ordinary affirmation. Affirmation is conditional when it depends on the possibility of excising objectionable elements from the object of affirmation. What Nietzsche means to reveal, with eternal recurrence, is that even the most apparently affirmative individuals often manifest only a conditional affirmation of life, a form of affirmation that conceals a tacit negation. Eternal recurrence brings this hidden negation to light, thereby encouraging us to move toward an unconditionally affirmative stance. I conclude by reflecting on why Nietzsche takes the distinction between conditional and unconditional affirmation to be such an important philosophical idea. I argue that those who devote themselves to challenging, long-term goals will face psychological pressures that tend to deform unconditional affirmation into conditional affirmation. (shrink)