Democracy or breakdown in Syria would change the whole Middle East overnight.

We know that advanced economies with stable governments that borrow in their own currency are capable of running up very high levels of debt without crisis.

The growth of the Internet will slow drastically, as the flaw in 'Metcalfe's law'–which states that the number of potential connections in a network is proportional to the square of the number of participants–becomes apparent: most people have nothing to say to each other! By 2005 or so, it will become clear that the Internet's impact on the economy has been no greater than the fax machine's.

People respond to incentives. If unemployment becomes more attractive because of the unemployment benefit, some unemployed workers may no longer try to find a job or may not try to find one as quickly as they would without the benefit.

When stock prices are rising, it's called ''momentum investing''; when they are falling, it's called ''panic.''

I've always believed that a speculative bubble need not lead to a recession, as long as interest rates are cut quickly enough to stimulate alternative investments. But I had to face the fact that speculative bubbles usually are followed by recessions. My excuse has been that this was because the policy makers moved too slowly - that central banks were typically too slow to cut interest rates in the face of a burst bubble, giving the downturn time to build up a lot of momentum.

So, very early reports are that Obamacare exchanges are, as expected, having some technical glitches on the first day - maybe even a bit worse than expected, because it appears that volume has been much bigger than predicted. Here’s what you need to know: this is good, not bad, news for the program... Lots of people logging on and signing up on the very first day... is an early indication that it’s going to be fine, that plenty of people will sign up for the first year of health reform.