The books that the world calls immoral are books that show the world its own shame.
Civilization is a race between disaster and education.
The deepest sin against the human mind is to believe things without evidence.
The ability to observe without evaluating is the highest form of intelligence.
All knowledge that the world has ever received comes from the mind; the infinite library of the universe is in our own mind.
Seek knowledge from the cradle to the grave.
Any knowledge that doesn't lead to new questions quickly dies out: it fails to maintain the temperature required for sustaining life.
A little knowledge is a dangerous thing. So is a lot.
Books are for people who wish they were somewhere else.
The delight of opening a new pursuit, or a new course of reading, imparts the vivacity and novelty of youth even to old age.
An investment in knowledge pays the best interest.
If the facts don't fit the theory, change the facts.
Any man who reads too much and uses his own brain too little falls into lazy habits of thinking.
If you can't explain it simply, you don't understand it well enough.
The only true wisdom is in knowing you know nothing.
The man who does not read good books has no advantage over the man who can't read them.
A witty saying proves nothing.
A man who has never gone to school may steal a freight car; but if he has a university education, he may steal the whole railroad.
Although modesty is natural to man, it is not natural to children. Modesty only begins with the knowledge of evil.
It is better to know how to learn than to know.
To educate a person in the mind but not in morals is to educate a menace to society.