Going from PayPal, I thought: 'Well, what are some of the other problems that are likely to most affect the future of humanity?' Not from the perspective, 'What's the best way to make money?'

When Henry Ford made cheap, reliable cars people said, 'Nah, what's wrong with a horse?' That was a huge bet he made, and it worked.

What I'm trying to do is to maximise the probability of the future being better.

I wouldn't say I have a lack of fear. In fact, I'd like my fear emotion to be less because it's very distracting and fries my nervous system.

I tend to approach things from a physics framework. And physics teaches you to reason from first principles rather than by analogy.

You could warm Mars up, over time, with greenhouse gases.

If you think back to the beginning of cell phones, laptops or really any new technology, it's always expensive.