Full Idea
I do not think that the Cartesians have ever proved or can prove that every perception is accompanied by consciousness.
Gist of Idea
Not all of perception is accompanied by consciousness
Source
Gottfried Leibniz (Principle of Life and Plastic Natures [1705], p.195)
Book Reference
Leibniz,Gottfried: 'Leibniz Selections', ed/tr. Wiener,Philip P. [Scribners 1951], p.195
A Reaction
This idea is very important in Leibniz, because non-conscious or barely conscious thoughts and perceptions explain a huge amount about behaviour, reality and morality.