A man is crazy who writes a secret in any other way than one which will conceal it from the vulgar.

Reasoning draws a conclusion, but does not make the conclusion certain, unless the mind discovers it by the path of experience.

Neglect of mathematics work injury to all knowledge, since he who is ignorant of it cannot know the other sciences or things of this world. And what is worst, those who are thus ignorant are unable to perceive their own ignorance, and so do not seek a remedy.

There are two modes of knowledge: through argument and through experience. Argument brings conclusions and compels us to concede them, but it does not cause certainty nor remove doubts that the mind may rest in truth, unless this is provided by experience.

Mathematics is the gate and key to science.

A man is crazy who writes a secret in any other way than one which will conceal it from the vulgar.

To ask the proper question is half of knowing.