Hoyt & Roberts, comps. Hoyts New Cyclopedia of Practical Quotations. 1922.
Uncertainty
Quis scit, an adjiciant hodiernæ crastina summæ Tempora di superi? Who knows whether the gods will add to-morrow to the present hour? HoraceCarmina. IV. 7. 17.
Omnia sunt hominum tenui pendentia filo: Et subito casu, quæ valuere, ruunt. All human things hang on a slender thread: the strongest fall with a sudden crash. OvidEpistolæ Ex Ponto. IV. 3. 35.
Dum in dubio est animus, paulo momento huc illuc impellitur. When the mind is in a state of uncertainty the smallest impulse directs it to either side. TerrenceAndria. I. 5. 32.