[zombot]

Are economists still trying to sell us the fairy tale that the market is rational?

[dismalaf]

The saying "the market is rational" simply means that assets are priced using all currently available information.

[zombot]

And then your bias makes you ignore all available information, so this doesn't mean anything.

[dismalaf]

Bias affects sentiment regarding future performance.

And it does mean things if you understand the meaning of the terms in the context of "finance".