I Once wrote: "In mathematics process and result are equivalent."

Whereof one cannot speak, thereof one must be silent.

We could present spatially an atomic fact which contradicted the laws of physics, but not one which contradicted the laws of geometry.

There can never be surprises in logic.

I am not interested in constructing a building, so much as in having a perspicuous view of the foundations of possible buildings.

The classifications made by philosophers and psychologists are like trying to classify clouds by their shape.

An inner process stands in need of outward criteria.