Full Idea
I have never thought that anything more is required to reveal a substance than its various attributes.
Gist of Idea
Knowing the attributes is enough to reveal a substance
Source
René Descartes (Reply to Fifth Objections [1641], 360)
Book Reference
Descartes,René: 'Meditations on First Philosophy etc.', ed/tr. Cottingham,John [CUP 1986], p.72