Some theories are good for nothing except to be argued about.

Nothing puts a greater obstacle in the way of the progress of knowledge than thinking that one knows what one does not yet know.

The most successful tempters and thus the most dangerous are the deluded deluders.

It is a question whether, when we break a murderer on the wheel, we do not fall into the error a child makes when it hits the chair it has bumped into.

If we make a couple of discoveries here and there we need not believe things will go on like this for ever. Just as we hit water when we dig in the earth, so we discover the incomprehensible sooner or later.

I am confident of my ability to demonstrate that one can sometimes believe in something and yet not believe in it. Nothing is less fathomable than the systems that motivate our actions.

The pleasures of the imagination are as it were only drawings and models which are played with by poor people who cannot afford the real thing.