Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.

Clarke’s aphorism frames the “Fermi paradox” as an existential dilemma rather than a technical puzzle. If humanity is alone, the universe’s vastness becomes a kind of cosmic indifference: intelligence is fragile, accidental, and carries the full burden of meaning and stewardship by itself. If we are not alone, the terror shifts to uncertainty—about the intentions, power, and incomprehensible otherness of extraterrestrial civilizations, and about humanity’s place in a larger hierarchy. The line’s force comes from its symmetry: either answer to the question of extraterrestrial life destabilizes human self-conception, making awe inseparable from dread.