Philosophy

eccentricity has always abounded when and where strength of character has abounded; and the amount of eccentricity in a society has generally been proportional to the amount of genius, mental vigor, and moral courage it contained
john stuart mill 1806 - 1873

experiment is the sole source of truth
henri poincare 1854 - 1912

words are also deeds
ludwig wittgenstein 1889 - 1951

there is no document of civilization which is not at the same time a document of barbarism
walter benjamin 1892 - 1940

philosophy, which once seemed obsolete, lives on because the moment to realize it was missed

theodor adorno 1903 - 1969

man makes himself; he is not found ready-made; he makes himself by the choice of his morality, and he cannot but choose a morality, such is the pressure of circumstance upon him

jean-paul sartre 1905 - 1980

Know thyself.

Thales of  Miletus (c. 625 - c. 545 BCE)

Know then that war is common, that justice is strife, and that all things come to be in accordance with strife and necessity

Heraclitus of Ephesus (c. 540 - c. 480 BCE)  

It is not the things themselves that disturb people but the judgements they make about these things.

Epictetus (55 - 135)

I am in a sorry state, for I do not even know what I do not know!

Saint Augustine (354 - 430)

There is nothing absurd in denying that God exists.

Saint Thomas Aquinas (1225 - 1274)

Whoever desires to be given everything must first give everything away.  

Meister Eckhart (1260 - 1327)

Power is everywhere; not because it embraces everything, but because it comes from everywhere.

Michel Foucault (1926 - 1984)

There are only, everywhere, differences and traces of traces.

Jacques Derrida (1930 - )