Full Idea
The action of thought by which one believes a thing, being different from that by which one knows that one believes it, they often exist the one without the other.
Gist of Idea
We can believe a thing without knowing we believe it
Source
René Descartes (A Discourse on Method [1637], §3.23)
Book Reference
Descartes,René: 'Discourse on Method/The Meditations', ed/tr. Sutcliffe,F.E. [Penguin 1968], p.46