Yeah, but so is nearly everything else. Money, sexuality and gender, architectural designs, military tradition, the list goes on without end. Nearly our entire society is a communicable memecomplex, and additionally, nearly every meme is logically incoherent, or at least logically unfounded.
By the very implied claim that you make that mental disorders exist, you also imply that there is such a thing as ordered mental states, correct patterns of thought, and healthy logical reasoning. This is a bold claim! You would do well to have less black-and-white reasoning.
Our bridges stand. Our rockets fly, and our planes (tend) to not drop out of the air unexpectedly. If not for some healthy logical reasoning, correct patterns of thought, and ordered mental states, then what? Yes, it's fun to discuss this kind of thing, and a lot of what we do is irrational, but it's just as often sophistry as anything else. I note, of course, that you did only say 'nearly', but that's basically exactly what I mean.
Mathematics and physics are memecomplices which allow us to study and consider the Platonic realm. There's no one single mathematics from a cultural perspective; consider where numerals, operators, and grouping come from. The notation is how we make sense of the abstract, non-physical aspects with our mere physical brains.
The "nearly" that I am exempting is for those things which are logically deduced from other things alone. While a person might reason incorrectly based on faulty premises, they are nonetheless using reason to do so, and applying it in a logical fashion (cf "formally formal" logic proofs). The right lesson to take away, I think, is that being logical, being consistent with empirical observations, and being uncontradicted by dialectic evidence, are three distinct things, and none of them are the truth, if the truth even exists.
I assert there are comparatively more ordered mental states, comparatively more correct patterns of thought, and comparatively healthier logical reasoning. None of that is black and white, and no one is perfect, but some do more harm, and some do more good. To claim otherwise is to abandon reason and hope when confronted with suffering. You have not done so; if not, why type at the internet?
I will take your first branch: Mental states are not observable, certainly not in a way which gives rise to some measure which we can call "orderedness". Study psychopathy and you'll see extremely "ordered" behaviors from people who are "suffering" from "mental disorders". At some point, the analogy becomes incoherent; human behaviors are too rich.
You may be interested in Aumann's Agreement: If two reasoners disagree, then either their reasoning differs, or their prior observations differ. It seems to me that typically it is the priors that differ. So why stigmatize folks for differing reasoning? Perhaps there is no good reason.
I can observe my own mental states, and I work to bring them into better alignment with my observations - more ordered. When I think it helpful to others, I use language to represent them. Because other's mental states are not directly obervable, I use a null hypothesis that they also use language to indicate their mental state.
When I use a regular expression, I have an intent to model an understanding. Some people may not have that vocabulary at all - my spouse, for instance. Some may be far more fluent than I. The point is: I have observed my understanding to be disordered or incomplete. I further observe that is the default state until I apply a degree of attention.
"Stigma" is an inaccurate model for when we don't have the resources to align another's goals with our own - goals which must include a baseline of wellbeing for every other. Persons suffering harmful hallucinations - or other harmful mental states - should be treated for them, but "stigma" is a blunt indicator to avoid conferring responsibility on those persons - I hold it an error to involve hatred or indifference. Our deficiencies in understanding are pervasive. I would not ask my spouse to develop a regular expression. They would not ask me to perform a phrase from a Mozart sonata.
Nope. There are scientific, verifiable, objective things (and nobody cares about epistemological problems).
As other post told: rockets fly, internet connects etc.
And there are subjective matters, like ethics, aesthetics, art, beauty.
Now, subjective doesn't mean bad. What I really dislike is things like philosophy (which critical theory is part of), which tries to cover subjective opinions with obscure rhetoric to make them appear as facts.
By the very implied claim that you make that mental disorders exist, you also imply that there is such a thing as ordered mental states, correct patterns of thought, and healthy logical reasoning. This is a bold claim! You would do well to have less black-and-white reasoning.