At some point, people may decide that the U.S. stock market has fallen enough. After all, the U.S. economy seems to be getting better, that what happens in China is not going to have that devastating effect on car sales here or how many people buy Apple phones or what happens at - how many people shop at Wal-Mart.

There is also a concern that there is a lack of demand of oil. And so when commodity prices fall, it's good if you happen to be a consumer, but it's sometimes seen as symptom of a weakening economy.

People have put a lot of faith in the government's ability to get growth going in China. People have this, what I think, illusion that there are six people in China who really have their hand on every button. And what we're learning is, it's a very big economy and they're not that good at it.

I think what the Fed fears is that, if Donald Trump gets big tax cuts and big spending increases that take effect right now, when the economy is close to full employment, they will have to raise rates more rapidly.

China's stock market is not very big. And yet when stock market has a bad day in China, it seems, Europe has a bad day and then we have a bad day.

I think it's hard to understand in economics. It's easier to understand on psychology.It's a kind of panic or a sense that the world economy is just not in as good shape as we thought and so everybody is chasing everybody else.

There is the fact that - people have had a lot of confidence that the Chinese leadership could fix what is wrong with their economy so it wouldn't have ripple effects around the world. I think that confidence is being shaken by how difficult it is for them to manage their stock market and their currency.