Mr. Soros, the chairman of Soros Fund Management, is best-known as a speculator, philanthropist and political activist. He made a fortune by doing things such as betting against Britain's currency in 1992 and Thailand's in 1997. A Hungarian refugee, he has spent millions to promote democracy and learning in post-Soviet nations.

When people retire, their income drops much more sharply than their consumption. As a result, they stop saving and start drawing down the assets they've acquired during their high-saving years. That could start to put upward pressure on interest rates and downward pressure on stock prices.

In the '70s, there were economists who argued that seat belts were causing people to drive faster and kill more pedestrians. But after 15 or 20 years of research, we can now conclude that's actually not true. Seat belts, on net, do make people safer. So, on an evidence-based process, we should have people wear seat belts.

It is probably the case that some regulation of financing will make crises less likely, and I would say higher capital requirements are an almost fail-safe way to make banks safer. But there are a lot of other things that may not be doing that, and so we need to be careful about sort of, like, rushing to one conclusion or another.