2.
You must first propound the theory and then explain the practice.
3.
Let no man who is not a mathematician read the principles of my work.
4.
In the course of scientific exposition the demonstration of a general rule derived from a previous conclusion is not to be censured.
Certainty of Mathematics
5.
He who blames the supreme certainty of mathematics feeds on confusion and will never be able to silence the contradictions or sophistical sciences which lead to an everlasting clamour.