Experience without theory is blind, but theory without experience is mere intellectual play.

He who never made a mistake, never made a discovery.

I am dying from the treatment of too many physicians.

It is piracy, not overt online music stores, which is our main competitor.

To forbid us anything is to make us have a mind for it.

The poor are prevented from thinking by the discipline of others, the rich by their own.

Many have had their greatness made for them by their enemies.

True valor lies between cowardice and rashness.

Delay always breeds danger. To protract a great design is often to ruin it.

An original idea. That can't be too hard. The library must be full of them.

A mediocre idea that generates enthusiasm will go further than a great idea that inspires no one.

Maybe, just once, someone will call me 'Sir' without adding, 'You're making a scene.'

I may not be better than other people, but at least I'm different.

Laziness never arrived at the attainment of a good wish.

Central banks don't have divine wisdom. They try to do the best analysis they can and must be prepared to stand or fall by the quality of that analysis.

A good goal is like a strenuous exercise - it makes you stretch.

I want to put a ding in the universe.

If everything isn't black and white, I say, 'Why the hell not?'

Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.

I have only ever read one book in my life, and that is White Fang. It's so frightfully good I've never bothered to read another.

Extraordinary claims require extraordinary evidence.