Goethe isn't simply reminding us that change happens—he's making a sharper claim: that *aliveness itself* requires active readiness, not mere passive acceptance. There's a difference between surviving change and being genuinely alive *during* it, and that difference lies in preparation. When a person loses their job at fifty and immediately begins retraining rather than sinking into resentment, they're not just coping; they're choosing to remain among "those who live." The weight of his word "must" suggests this isn't optional—clinging to what was, refusing to adapt, is a slow retreat from life itself.