Just a few that I like:
Quote:"They [preachers] dread the advance of science as witches do the approach of daylight and scowl on the fatal harbinger announcing the subversions of the duperies on which they live".
-Thomas Jefferson
"The mind—once enlightened—cannot again become dark."
-Thomas Paine
"Why should I fear death? If I exist, then death is not. If death exists, then I am not. Why should I fear that which cannot exist while I do?"
-Epicurus
"If you could reason with religious people, there would be no religious people."
-House
"I contend that we are both atheists. I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours."
-Stephen Roberts
"It's easier to fool people than to convince them that they have been fooled."
-Mark Twain