Mistakes are, after all, the foundations of truth, and if a man does not know what a thing is, it is at least an increase in knowledge if he knows what it is not.

Knowledge rests not upon truth alone, but upon error also.

The healthy man does not torture others - generally it is the tortured who turn into torturers.

I do not believe...I know.

The word 'belief' is a difficult thing for me. I don't believe. I must have a reason for a certain hypothesis. Either I know a thing, and then I know it - I don't need to believe it.

He who knows, does not speak. He who speaks, does not know.