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Without dreams, one cannot go on living.
Literal
Dreams [even-も] if-not-exist cannot-live.
夢もなければ生きられない — a conditional negative: 'if there aren't even dreams, one can't live.' The も adds emphasis ('not even dreams'). なければ is the negative conditional of ある. 生きられない is the negative potential of 生きる. The sentence reads as a philosophical aphorism — compact and universal.