Felix, qui potuit rerum cognoscere causas

"Felix, qui potuit rerum cognoscere causas" is verse 490 of Book 2 of the Georgics (29 BC), by the Latin poet Virgil (70 – 19 BC). It is literally translated as: "Fortunate, who has been able to know the causes of things". Dryden rendered it: "Happy the Man, who, studying Nature's Laws, / Thro' known Effects can trace the secret Cause" (The works of Virgil, 1697).

Virgil may have had in mind the Roman philosopher Lucretius, of the Epicurean school.