Mathematics is the only instructional material that can be presented in an entirely undogmatic way.

How can it be that mathematics, being after all a product of human thought independent of experience, is so admirably adapted to the objects of reality?

As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.

Do not worry about your difficulties in mathematics, I assure you that mine are greater.

With me everything turns into mathematics. [Fr., Omnia apud me mathematica fiunt.]

Pure mathematics is, in its way, the poetry of logical ideas.