My own answer to the contrarian question is that most people think the future of the world will be defined by globalization, but the truth is that technology matters more.

One of the reasons I think people are increasingly nervous about U.S. debt is because they think that we are not actually digging ourselves out of the hole, but instead are digging ourselves into a deeper and deeper hole and will not be able to pay it back because we're not actually creating the new technologies that will enable us to pay back and the money somehow is not really being invested in the future or in progress.

If you focus on near-term growth above all else, you miss the most important question you should be asking: will this business still be around a decade from now?

When you already have $150 billion a year in revenues from the iPhone, it's very hard to come up with any new vertical that will sort of move the dial. And there's this sort of weird effect where the larger a company gets, the harder it is to come up with any new product that really moves the dial.

A true bubble is when something is overvalued and intensely believed.

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.

But the indeterminate future is somehow one in which probability and statistics are the dominant modality for making sense of the world. Bell curves and random walks define what the future is going to look like. The standard pedagogical argument is that high schools should get rid of calculus and replace it with statistics, which is really important and actually useful. There has been a powerful shift toward the idea that statistical ways of thinking are going to drive the future.