Advice like these are not laws. They are like hats. If one doesn’t fit， try another.

There is no perfect knowledge which can be entitled ours, that is innate; none but what has been obtained from experience.

"The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion."

I am happy and proud of what I have done， but not completely satisfied.

"Mathematics is the science of patterns, and nature exploits just about every pattern that there is."