You should be innovating so fast that you're invalidating your prior patents.

I think it's important to reason from first principles rather than by analogy. The normal way we conduct our lives is we reason by analogy. [With analogy] we are doing this because it's like something else that was done, or it is like what other people are doing. [With first principles] you boil things down to the most fundamental truths…and then reason up from there.

I'm reasonably optimistic about the future, especially the future of the United States - for the century, at least.

We're running the most dangerous experiment in history right now, which is to see how much carbon dioxide the atmosphere can handle before there is an environmental catastrophe.

Optimism, pessimism, f**k that; we're going to make it happen. As God is my bloody witness, I'm hell-bent on making it work.

Facebook is quite entrenched and has a network effect. It's hard to break into a network once it's formed.

Physics is really figuring out how to discover new things that are counterintuitive, like quantum mechanics. It's really counterintuitive.