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 indeed amazed when I consider how weak my mind is and how prone to error.

I am accustomed to sleep and in my dreams to imagine the same things that lunatics imagine when awake.

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

The reading of all good books is like a conversation with the finest minds of past centuries.