Experience by itself is not science.

In all the areas within which the spiritual life of humanity is at work, the historical epoch wherein fate has placed us is an epoch of stupendous happenings.

The ideal of a pure phenomenology will be perfected only by answering this question; pure phenomenology is to be separated sharply from psychology at large and, specifically, from the descriptive psychology of the phenomena of consciousness.

To every object there correspond an ideally closed system of truths that are true of it and, on the other hand, an ideal system of possible cognitive processes by virtue of which the object and the truths about it would be given to any cognitive subject.

If all consciousness is subject to essential laws in a manner similar to that in which spatial reality is subject to mathematical laws, then these essential laws will be of most fertile significance in investigating facts of the conscious life of human and brute animals.

Without troublesome work, no one can have any concrete, full idea of what pure mathematical research is like or of the profusion of insights that can be obtained from it.

Merely fact-minded sciences make merely fact-minded people.