I think a lot of economics is neither rational or irrational. Emergent systems tend to be like this, and it contradicts a lot of our intuition about how systems

I think a lot of economics is neither rational or irrational. Emergent systems tend to be like this, and it contradicts a lot of our intuition about how systems should be. I think we should look at the stock market as part of the monetary system. In some sense, this is at the heart of "capitalism." Capitalism has become a very complex term after 200 years of complex use, but in most versions it's dated to the Dutch and British empires' systems of chartered companies, tradeable bonds, and stocks. Bubbles occurred from the very start, which basically means unsustainably irrational. But (imo) it's a mistake to assume that anything short of a bubble is/was rational. The textbook (rational) definitions of "value" are only determinable in retrospect. But, this is pretty theoretical. It's quite rare that a traded company justifies its value in dividends, regardless of profit. This is why the total market cap keeps growing.