This inescapable duty to observe oneself: if someone else is observing me, naturally I have to observe myself too; if none observe me, I have to observe myself all the closer

How pathetically scanty my self-knowledge is compared with, say, my knowledge of my room. There is no such thing as observation of the inner world, as there is of the outer world.

A stair not worn hollow by footsteps is, regarded from its own point of view, only a boring something made of wood.

Books are a narcotic

In argument similes are like songs in love; they describe much, but prove nothing.

You may object that it is not a trial at all; you are quite right, for it is only a trial if I recognize it as such.