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

To live without philosophizing is in truth the same as keeping the eyes closed without attempting to open them.

When writing about transcendental issues, be transcendentally clear.

Illusory joy is often worth more than genuine sorrow.

I did not imitate the skeptics who doubt only for doubting's sake, and pretend to be always undecided; on the contrary, my whole intention was to arrive at a certainty, and to dig away the drift and the sand until I reached the rock or the clay beneath.

The greatest minds are capable of the greatest vices as well as of the greatest virtues.

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