There is a little gland in the brain in which the soul exercises its functions in a more particular way than in the other parts.

There is a great difference between mind and body insomuch as body is by nature always divisible, and the mind is entirely indivisible.

The nature of matter, or body considered in general, consists not in its being something which is hard or heavy or coloured, or which affects the senses in any way, but simply in its being something which is extended in length, breadth and depth.

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.

Wonder is the first of all the passions.

For each of us there is a set limit to our intellectual powers which we cannot pass.

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