We're short on wisdom; we're high on technology. Where's it going to lead?

Anyone who's not interested in model airplanes must have a screw loose somewhere.

The only dumb question is the question you don't ask.

The problem is we don't understand the problem.

Your grandchildren will likely find it incredible - or even sinful - that you burned up a gallon of gasoline to fetch a pack of cigarettes!

I'm more interested in a world that works than what sells.

The surviving intelligent life form on Earth is not going to be carbon-based; it's going to be silicon-based.

No man is equal to his book. All the best products of his mental activity go into his book, where they come separated from the mass of inferior products with which they are mingled in his daily talk.

Love of our neighbour, then, has just the same respect to, is no more distant from, self-love, than hatred of our neighbour, or than love or hatred of anything else.

It looks good when you see someone kicking at the age of 51 with no double. It's kinda cool for people to know that past 50 we can keep flexible.

I love it when people want to interpret my books.

Being in the wrong place never helps you do the right thing

I think the most alarming animals I have encountered are really poisonous snakes.

A visual sense is something you either have or you don't.

Just keep working. I've been working hard, so just keep on doing what I've been doing.

Think of yourself as dead. You have lived your life. Now, take what's left and live it properly. What doesn't transmit light creates its own darkness.

You mustn't always believe what I say. Questions tempt you to tell lies, particularly when there is no answer.