I think Lumifer is suggesting that a model can correspond accurately to reality (e.g., representing the fact that X is in a hot air balloon 30 feet above Y's current location) but none the less be useless (e.g., because all X wants to know is how to get to Vladivostok, and knowing he's in a balloon 30 feet above Y doesn't help with that). And that this is an example of how a model can be "bad" other than inaccurate correspondence with reality, which is what you were asking for a few comments upthread.
A couple of days ago, Buybuydandavis wrote the following on Less Wrong:
I've spent a lot of energy over the last couple of days trying to come to terms with the implications of this sentence. While it certainly corresponds with my own observations about many people, the thought that most humans simply reject correspondence to reality as the criterion for truth seems almost too outrageous to take seriously. If upon further reflection I end up truly believing this, it seems that it would be impossible for me to have a discussion about the nature of reality with the great majority of the human race. In other words, if I truly believed this, I would label most people as being too stupid to have a real discussion with.
However, this reaction seems like an instance of a failure mode described by Megan McArdle:
With this background, it seems important to improve my model of people who reject correspondence as the criterion for truth. The obvious first place to look is in academic philosophy. The primary challenger to correspondence theory is called “coherence theory”. If I understand correctly, coherence theory says that a statement is true iff it is logically consistent with “some specified set of sentences”
Coherence is obviously an important concept, which has valuable uses for example in formal systems. It does not capture my idea of what the word “truth” means, but that is purely a semantics issue. I would be willing to cede the word “truth” to the coherence camp if we agreed on a separate word we could use to mean “correspondence to reality”. However, my intuition is that they wouldn't let us to get away with this. I sense that there are people out there who genuinely object to the very idea of discussing whether a sentences correspond to reality.
So it seems I have a couple of options:
1. I can look for empirical evidence that buybuydandavis is wrong, ie that most people accept correspondence to reality as the criterion for truth
2. I can try to convince people to use some other word for correspondence to reality, so they have the necessary semantic machinery to have a real discussion about what reality is like
3. I can accept that most people are unable to have a discussion about the nature of reality
4. I can attempt to steelman the position that truth is something other than correspondence
Option 1 appears unlikely to be true. Option 2 seems unlikely to work. Option 3 seems very unattractive, because it would be very uncomfortable to have discussions that on the surface appear to be about the nature of reality, but which really are about something else, where the precise value of "something else" is unknown to me.
I would therefore be very interested in a steelman of non-correspondence concepts of truth. I think it would be important not only for me, but also for the rationalist community as a group, to get a more accurate model of how non-rationalists think about "truth"