The delight of opening a new pursuit, or a new course of reading, imparts the vivacity and novelty of youth even to old age.

What is freedom of expression? Without the freedom to offend, it ceases to exist.

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

When you know better you do better.

Never help a child with a task at which he feels he can succeed.

If you're teaching today what you were teaching five years ago, either the field is dead or you are.

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.

All knowledge that the world has ever received comes from the mind; the infinite library of the universe is in our own mind.

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

Patience is a virtue, and I'm learning patience. It's a tough lesson.

Physics is like sex: sure, it may give some practical results, but that's not why we do it.

Reading is to the mind what exercise is to the body.

I am a part of everything that I have read.

What is now proved was once only imagined.

Reading furnishes the mind only with materials of knowledge; it is thinking that makes what we read ours.

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

Know what you are talking about.

The highest result of education is tolerance.

Investigate, educate and organize.

The whole of science is nothing more than a refinement of everyday thinking.

The secret of life is not enjoyment but education through experience.