Nothing is more important for teaching us to understand the concepts we have than to construct fictitious ones.

It is an hypothesis that the sun will rise tomorrow: and this means that we do not know whether it will rise.

He who lives in the present lives in eternity.

A French politician once wrote that it was a peculiarity of the French language that in it words occur in the order in which one thinks them.

The human body is the best picture of the human soul.

What is left over if I subtract the fact that my arms goes up from the fact that I raise my arm?

The sense of the world must lie outside the world... What we cannot speak about we must remain silent about... What can be described can happen too, and what is excluded by the laws of causality cannot be described.