When I am attacked by gloomy thoughts, nothing helps me so much as running to my books. They quickly absorb me and banish the clouds from my mind.

I decided to teach because I think that any person who studies philosophy has to be involved actively.

Don't learn to do, but learn in doing.

To every action there is always an equal and opposite or contrary, reaction

God created man in His own image, says the Bible; philosophers reverse the process: they create God in theirs.

Common sense is the collection of prejudices acquired by age eighteen.

All stable processes we shall predict. All unstable processes we shall control.

Dare to think for yourself.

The only good is knowledge and the only evil is ignorance.

It took us three years to build the NeXT computer. If we'd given customers what they said they wanted, we'd have built a computer they'd have been happy with a year after we spoke to them - not something they'd want now.

No man's knowledge here can go beyond his experience.

Know what you are talking about.

Evil being the root of mystery, pain is the root of knowledge.

To educate a person in the mind but not in morals is to educate a menace to society.

My weapon is literature

Although modesty is natural to man, it is not natural to children. Modesty only begins with the knowledge of evil.

Liberty without Learning is always in peril and Learning without Liberty is always in vain.

Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it.

They say a little knowledge is a dangerous thing, but it's not one half so bad as a lot of ignorance.

As we acquire more knowledge, things do not become more comprehensible but more mysterious.

Books are for people who wish they were somewhere else.