Whereof one cannot speak, thereof one must be silent. There can never be surprises in logic. The riddle does not exist. If a question can be put at all, then it can also be answered. Everything that can be said, can be said clearly.
All mathematics is tautology.
The process of calculating brings about just this intuition. Calculation is not an experiment. A mathematical proof must be perspicuous. There is no religious denomination in which the misuse of metaphysical expressions has been responsible for so much sin as it has in mathematics. With my full philosophical rucksack I can only climb slowly up the mountain of mathematics.