Jeff Guo

A truce.

Because Robin's paper, it doesn't exactly prove Fama wrong.

It is still really hard to detect bubbles.

When it comes to bubbles, there are basically two types of people who obsess about them.

There are, of course, investors who are worried about losing their money in a potential bubble.

But these days, there's also big, important people in the government who are worried about what bubbles mean for, you know, the whole national economy.

Hold on.

Who came up with this?

Was it really called lean versus clean?

And this whole lean versus clean debate, this is a recent thing.

When Gotti was in grad school in the 90s, nobody thought bubbles were something that serious macroeconomists needed to be studying, especially not macroeconomists who were focused on the U.S.

Yeah.

So all of a sudden, macroeconomists, they became very interested in bubbles.

Some argued that if we can spot a bubble, which is a big if, but if we can, shouldn't we go in and fix it?

But the clean side of the debate was like, we are horrible at predicting bubbles.

And there's a good chance that if we step in, we'll just do more harm than good.

So let's just wait it out and we'll clean it up afterward.

Right.

Number one, bubbles hurt the economy, of course, when they pop.

But not all bubbles cause the same amount of economic damage when they pop.