We're only really thinking when we can't think out fully what we are really thinking about!

Never by reflection, but only by doing is self- knowledge possible to one.

In all times it is only individuals that have advanced science, not the age.

If you wish a wise answer, you must put a rational question.

Choose well. Your choice is brief, and yet endless.

We do not have to visit a madhouse to find disordered minds; our planet is the mental institution of the universe.

Theories are usually the over-hasty efforts of an impatient understanding that would gladly be rid of phenomena, and so puts in their place pictures, notions, nay, often mere words.