Full Idea
Rationality is now an internal property of subjective thinking, rather than its consisting in (according to Plato) its vision of reality. This view of Descartes' has become the standard modern view.
Gist of Idea
Descartes created the modern view of rationality, as an internal feature instead of an external vision
Source
report of René Descartes (Meditations [1641]) by Charles Taylor - Sources of the Self §8
Book Reference
Taylor,Charles: 'Sources of the Self' [CUP 1992], p.156
A Reaction
Greek 'logos' actually seemed to be both internal and external. We have certainly lost the idea that the universe is rational, even though it is ordered.