Two things fill the mind with ever new and increasing admiration and reverence: the starry heavens above me and the moral law within me.

Have the courage to use your own understanding!

Treat humanity, in your own person or in another, always as an end and never merely as a means.

I had to deny knowledge in order to make room for faith.

For thinking and Being are the same.

-- Parmenides

You must learn all things: both the steadfast heart of well-rounded Truth and the opinions of mortals, in which there is no true trust.

-- Parmenides

Imagine prisoners chained underground since childhood, seeing only shadows on a wall and taking them for reality.

-- Plato

I know that I know nothing.

-- Socrates

Color exists by convention, sweet by convention, bitter by convention; in reality there are only atoms and void.

-- Democritus

Those who understand that things arise dependently know them to be empty.

-- Nagarjuna