Full Idea
Descartes transformed the proposition 'because God is thinkable, therefore he exists' into the proposition 'I think, therefore I am'.
Gist of Idea
Descartes transformed 'God is thinkable, so he exists' into 'I think, so I exist'
Source
report of René Descartes (Meditations [1641], 2) by Ludwig Feuerbach - Principles of Philosophy of the Future §18
Book Reference
Feuerbach,Ludwig: 'Principles of the Philosophy of the Future', ed/tr. Vogel,M [Hackett 1986], p.31
A Reaction
This implies that Descartes' foundation is the Ontological Argument rather than the Cogito. It certainly shows how a priori synthetic thinking is basic in Descartes - that views of existence derive from pure thought. Was Descartes an idealist?