“. . .it is not my design to teach the method that everyone must follow in order to use his reason properly, but only to show the way in which I have tried to use my own.”

“It is not enough to have a good mind; the main thing is to use it well.”

“This result could have been achieved either by his [God] endowing my intellect with a clear and distinct perception of everything about which I would ever deliberate, or simply by impressing the following rule so firmly upon my memory that I could never forget it: I should never judge anything that I do not clearly and distinctly understand.”

“Because reason...is the only thing that makes us men, and distinguishes us from the beasts, I would prefer to believe that it exists, in its entirety, in each of us...”

“It is not enough to have a good mind. The main thing is to use it well.”

“It is only prudent never to place complete confidence in that by which we have even once been deceived.”

“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 the increasing discovery of my own ignorance”