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.

Illusory joy is often worth more than genuine sorrow.

So far, I have been a spectator in this theater which is the world, but I am now about to mount the stage, and I come forward masked.

The rainbow is such a remarkable phenomenon of nature, and its cause has been so meticulously sought after by inquiring minds throughout the ages, that I could not choose a more appropriate subject for demonstrating how, with the method I am using, we can arrive at knowledge not possessed at all by those whose writings are available to us.

Wonder is the first of all the passions.

He who hid well, lived well.

It is possible that I am dreaming right now and that all of my perceptions are false.