In a world where wealth is growing, you can get away with printing money. Doubling the debt over the next 20 years is not a problem.

I do think Bitcoin is the first [encrypted money] that has the potential to do something like change the world.

People don't want to believe that technology is broken. Pharmaceuticals, robotics, artificial intelligence, nanotechnology - all these areas where the progress has been a lot more limited than people think. And the question is why.

Anti-aging is an extremely under-explored field.

The developing world can just do things that are extensive or horizontal, that basically copy. The developed world needs to do things that are intensive or vertical, where we take our civilization to the next level.

Twitter is hard to evaluate. They have a lot of potential. It's a horribly mismanaged company — probably a lot of pot-smoking going on there. But it's such a solid franchise it may even work with all that.

It's a horribly mismanaged company-probably a lot of pot smoking going on there.