[cybernautique]

Irrational in what sense? I can, indeed, claim that NFTs have value to even a purely rational actor, if I'm allowed to ascribe self-determination to that actor.

Particularly, I think it's important to delineate whether 'rationality' allows for arbitrary actions, decisions, and desires. I do include these qualities in my notion of rationality, so long as the actor can rationalize the phenomena to themselves (even if this rationalization is based on nothing more than their ability to do so).

Given this notion of value and rationality, yes: I can very easily allow for NFTs ('useless' though they are) having value.

Do you mean 'rational' in terms of 'every action or desire is reducible to some unknown deductive logic'? In which case, I agree that everyone is somewhat irrational and furthermore that nobody could ever be rational. 'Rational' in the game theory sense? In which case, I see no reason to say that everyone is irrational instead of allowing for the mathematical notion imperfectly capturing reality.

[philosopher1234]

If everyone is buying NFTs because they believe the price is going to go up, and they tell themselves that the reason the price is going up is because NFTs are useful, but in reality NFTs are not, that is irrational. So it allows them to have monetary value while contributing nothing useful to the economy, and in fact causing people harm.

It is possible NFTs do have value in the sense of being good, but them being priced highly does not give us useful signal there.

[cybernautique]

That's not irrational in the sense of there lacking inherent reasoning or rationalization, it's just a poor deduction. If you mean that rational agents are incapable of flawed reasoning, then I agree that humans are somewhat irrational (and further that no human could ever be rational).

I suppose my biggest gripe is this: how do you construct a notion of rationality which allows for some people to be perfectly rational sometimes, imperfectly rational at other times, and others to be rational never, while allowing for real flaws in reasoning and the absence of perfect information? (this is, to me, a rough sketch of some necessary/sufficient conditions)

[philosopher1234]

I think irrational is something like retaining a false belief despite it being clear that it is false. It’s got something to do with holding on to a point of view despite its inadequacy.

[cybernautique]

Then much of science is irrational; what about those times where it's understood that a belief is false, but it also holds the most explanative power of all other considered beliefs?

And, again, the notion that something is 'clearly false' at some point presupposes perfect information about the context within which the belief is held.