A battery by definition is a collection of cells. So the cell is a little can of chemicals. And the challenge is taking a very high-energy cell, and a large number of them, and combining them safely into a large battery.

I think we should be very careful about artificial intelligence. If I had to guess at what our biggest existential threat is, it's probably that. So we need to be very careful...With artificial intelligence we're summoning the demon.

Some companies out there quote a start of production that is substantially in advance of when customers get their cars.

If you go back back a few hundred years, what we take for granted today would seem like magic - being able to talk to people over long distances, to transmit images, flying, accessing vast amounts of data like an oracle. These are all things that would have been considered magic a few hundred years ago.

It's obviously tricky to convert cellulose to a useful biofuel. I think actually the most efficient way to use cellulose is to burn it in a co-generation power plant. That will yield the most energy and that is something you can do today.

You need to live in a dome initially but over time you could terraform Mars to look like Earth and eventually walk around outside without anything on. ... So it's a fixer-upper of a planet.

I do think there is a lot of potential if you have a compelling product and people are willing to pay a premium for that. I think that is what Apple has shown. You can buy a much cheaper cell phone or laptop, but Apple's product is so much better than the alternative, and people are willing to pay that premium.