Considered logically this concept is not identical with the totality of sense impressions referred to; but it is an arbitrary creation of the human (or animal) mind.

All conditions and all circumstances in our lives are a result of a certain level of thinking. If we want to change the conditions and circumstances, we have to change the level of thinking that is responsible for it.

To the extent math refers to reality, we are not certain to the extent we are certain, math does not refer to reality.

A true genius admits that he/she knows nothing.

Genius simply cannot be reduced to a set of rules for anyone to follow.

One should never impose one's views on a problem; one should rather study it, and in time a solution will reveal itself.

Imagination is greater than knowledge.