Sometimes I think we're alone. Sometimes I think we're not. In either case, the thought is staggering.

The earth is like a spaceship that didn't come with an operating manual.

Humanity is acquiring all the right technology for all the wrong reasons.

You can never learn less, you can only learn more.

Tension is the great integrity.

We are called to be architects of the future, not its victims.

Those who play with the devil's toys will be brought by degrees to wield his sword.

Man knows so much and does so little.

I look for what needs to be done. After all, that's how the universe designs itself.

Most of my advances were by mistake. You uncover what is when you get rid of what isn't.

The most important thing about Spaceship Earth - an instruction book didn't come with it.

A proverb is much matter distilled into few words.

Dictators never invent their own opportunities.

I just invent, then wait until man comes around to needing what I've invented.

If you are the master be sometimes blind, if you are the servant be sometimes deaf.

Rashness is the faithful, but unhappy parent of misfortune.

Truth is a tendency.

War is the ultimate tool of politics.

Gold and silver from the dead turn often into lead.

Here is God's purpose - for God, to me, it seems, is a verb not a noun, proper or improper.