Full Idea
Everything that is observed or grasped by the intellect in an act of application is true.
Gist of Idea
Observation and applied thought are always true
Source
Epicurus (Letter to Herodotus [c.293 BCE], 62)
Book Reference
Epicurus: 'The Epicurus Reader', ed/tr. Inwood,B. /Gerson,L. [Hackett 1994], p.13
A Reaction
Not quite clear what he means, but Epicurus is committed to perception as the source of knowledge, with the intellect extending the findings of the senses. He might subscribe to Descartes's 'clear and distinct' perceptions.