Full Idea
Since Descartes conceives of God as existing necessarily, whether I exist to think of him or not, Descartes assures me of a possible access to an absolute reality - a Great Outdoors that is not a correlate of my thought.
Gist of Idea
The ontological proof of a necessary God ensures a reality external to the mind
Source
Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 2)
Book Reference
Meillassoux: 'After Finitude: the necessity of contingency', ed/tr. Brassier,R [Bloomsbury 2008], p.29
A Reaction
His point is that the ontological argument should be seen as part of the scientific revolution, and not an anomaly within it. Interesting.