An inner process stands in need of outward criteria.

Never stay up on the barren heights of cleverness, but come down into the green valleys of silliness.

A serious and good philosophical work could be written consisting entirely of jokes.

Don't ask what it means, but rather how it is used.

Philosophy is like trying to open a safe with a combination lock: each little adjustment of the dials seems to achieve nothing, only when everything is in place does the door open.

The object of philosophy is the logical clarification of thought.

What we cannot speak about we must pass over in silence.