I live in that solitude which is painful in youth, but delicious in the years of maturity.

I never teach my pupils, I only attempt to provide the conditions in which they can learn.

Whoever is careless with the truth in small matters cannot be trusted with important matters.

Nothing truly valuable can be achieved except by the unselfish cooperation of many individuals.

The distinction between the past, present and future is only a stubbornly persistent illusion.

Any man who reads too much and uses his own brain too little falls into lazy habits of thinking.

Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning.

Most people say that it is the intellect which makes a great scientist. They are wrong: it is character.