recta ratio

The story

1. Ancient Greek · derived fromὀρθὸς λόγος
2. Latin · borrowed fromrēcta ratiō“right reason”
3. English todayrecta ratio

First attested in an English text in 1677; borrowed from Latin rēcta ratiō (“right reason”), a calque of Ancient Greek ὀρθὸς λόγος (orthòs lógos). Cf. Cicero, De leg. I, 7, I, 2: “Recta ratio - quae cum sit lex, lege quoque consociati homines cum diis putandi sumus.” Term used in a letter to "Tom" by John Locke, October 20, 1659: “...We are all centaurs, and ’tis the beast that carries us, and everyone’s recta ratio is but the traverses of his own steps.”