He who postpones the hour of living well, like the hind [in the fable], waits till [all the water in] the river be run off: whereas it flows, and will flow, ever rolling on. … He has half the deed done, who has made a beginning. Boldly undertake the study of true wisdom: begin it forthwith.
Smart/Buckley’s prose rendering of Epistles 1.2.40–41; the bracketed gloss is the translator’s. Horace’s Latin sentence pivots from “dimidium facti…” straight into “sapere aude, incipe” — the “dare to be wise” line Kant later made a motto of the Enlightenment.
✓Public domain
The displayed English is Christopher Smart’s prose translation, first published 1756 and revised by Theodore Alois Buckley in 1853 — both well before 1931, so this rendering is in the public domain in the United States. (Horace’s underlying Latin has of course been public for two millennia.)
⚠ This reflects the original work, which is public domain. If your exact English wording comes from a specific modern translation, that translation may itself still be under copyright — check the edition you quote.