Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has.

A person has two passions for love and abhorrence. A big disposition to excessiveness has just a love, because it is more ardent and stronger.

Human wisdom remains always one and the same although applied to the most diverse objects and it is no more changed by their diversity than the sunshine is changed by the variety of objects which it illuminates.

The two operations of our understanding, intuition and deduction, on which alone we have said we must rely in the acquisition of knowledge.

I am thinking, therefore I exist. (...) I was a substance whose whole essence or nature is solely to think, and which does not require any place, or depend on any material thing, in order to exist. Accordingly this 'I' - that is, the soul by which I am what I am - is entirely distinct from the body, and indeed is easier to know than the body, and would not fail to be whatever it is, even if the body did not exist.

Common sense is the most widely shared commodity in the world, for every man is convinced that he is well supplied with it.

For I found myself embarrassed with so many doubts and errors that it seemed to me that the effort to instruct myself had no effect other than th eincreasing discovery of my own ignorance