Full Idea
I have very clearly deduced the following truths, that there is a God who is the author of all that is in the world, and who is the source of all truth.
Gist of Idea
I know the truth that God exists and is the author of truth
Source
René Descartes (Preface to 'Principles of Philosophy' [1647], p.180)
Book Reference
Descartes,René: 'Discourse on Method/The Meditations', ed/tr. Sutcliffe,F.E. [Penguin 1968], p.180