You might not have noticed, but financial markets have gone kind of nuts.

They don’t seem to be following the old rules that governed stocks and other investments in the past. Generally, bad news drove stocks down. Small investors like me (and they don’t get much smaller) would get nervous whenever confidence-rattling news like a trade conflict popped up.

Whether or not you sell stocks when you receive bad tidings, the sense that there’s a relationship between rotten news and market dives gives the comforting feeling that you just might understand economics, at least a little.

But today’s rising stock market seems to defy gravity. Nothing really slows it down for long, at least so far: not trade wars, domestic political deadlock and strife, international tensions or, of course, the increasingly obvious disaster of climate change.

I’m not claiming that we’ve done away with the business cycle of booms and busts. Supposedly smart people made that claim in the 1990s and in 2000, during the dot-com boom. Technological innovation had helped create a New Economy that would leave the business cycle in the dustbin of economic history, or something like that.