Love is the child of illusion and the parent of disillusion.
Science is a cemetery of dead ideas.
A lot of good arguments are spoiled by some fool who knows what he is talking about
Only in solitude do we find ourselves; and in finding ourselves, we find in ourselves all our brothers in solitude.
The skeptic does not mean him who doubts, but him who investigates or researches, as opposed to him who asserts and thinks that he has found.
To fall into a habit is to begin to cease to be.
The greatest height of heroism to which an individual, like a people, can attain is to know how to face ridicule
When a thing is said to be not worth refuting you may be sure that either it is flagrantly stupid -- in which case all comment is superfluous -- or it is something formidable, the very crux of the problem.