Elaboration of Vasubandhu's argument for the possibility of mental appearances to be publicly sharable? The vivid qualitative experience of a word (or called &quot;quale&quot; as a philosophical jargon, &quot;private language&quot; as a linguistic jargon) formed by each person is intrinsically different due to one's knowledge, environment, mood, past experience, etc, even same person may form completely different private language's words at different times for a same public language word.
I once see reference here in Wikipeda, without elaboration, that the famous ancient Buddhist Yogacaraist Vasubandhu

uses the example of mass hallucinations (in Buddhist hell) to defend against those who would doubt that mental appearances can be shared.

Can anyone elaborate any historical accounts/stories or speculative explanation about Vasubandhu's argument referenced above to argue for the possibility of mental appearances to be publicly sharable? If such sharing cannot be made exactly on the same common ground, then will there always be some confusion and difference between any two people no matter what cognitive level they achieved?
As a side note, I know this is very similar to the Problem of Other Minds in modern social science where scholars and philosophers invented a term &quot;intersubjectivity&quot; defined here to objectify the existence of certain social common &quot;thought communities&quot; one unavoidably belongs to explain why people can share their private intrinsically different experiences. But I think this community-wise intersubjectivity is just like the sound of a chorus which can be entirely reduced to the superposition of individual sounds, thus seems not a necessary concept. Also per Buddhism's doctrine, the source of suffering is from objectifying private conscious experience and the following endless craving of such reified object, so I'm also interested in hearing any other different middle-way Madhyamaka-style explanations from Yogacara or any other Buddhist schools... Or does Buddhism never have an answer for such question as it belongs to papañca (conception proliferation) and thus effectively reject true possibility of exact mental appearances sharing like in the purely neutral and rational math-like ideal-forms realm?
There is a famous allegory in Mahayana Buddhism relating three different beings' experience of the very same cup of liquid. The first being is a God, the second is a human, and the third is a hungry ghost. To the God, the cup full of liquid is experienced as a golden chalice full of the most wonderful crystal clear ambrosia giving off a mesmerizing scent. To the human being it is a rather ordinary cup of water. To the hungry ghost it's a revolting and ugly basin full of blood and pus.
Then the Buddhist student is asked to consider what is the truth of this object? Is it a chalice of amazing elixir? Just a cup of water? A vile concoction of mucus and phlegm? And what is it to an ant? An ocean? Is it something else? All of these things at the same time? How about to other humans? To other gods? To other beings? Could it be that there are countless experiences of the same &quot;thing&quot; all related to the karma of the beings experiencing it?
A western philosophical student might wonder what is the qualia of this object? How can different beings experience such different qualia of the same underlying object? Is it &quot;the same&quot; underlying object?? If so, how can it have different qualia? If it is not the same, then what is it? Can anything at all be objectively measured and understood and experienced the same by all beings that might encounter it? By some subsets but not others?

&quot;As a side note, I know this is very similar to the Problem of Other
Minds in modern social science where scholars and philosophers
invented a term &quot;intersubjectivity&quot; defined here to objectify the
existence of certain social common &quot;thought communities&quot; one
unavoidably belongs to explain why people can share their private
intrinsically different experiences.&quot;

I think that is a very poor set of definitions. From all I can tell, it sounds like &quot;intersubjectivity&quot; is merely another word for &quot;convention.&quot;

But I think this community-wise intersubjectivity is just like the
sound of a chorus which can be entirely reduced to the superposition
of individual sounds, thus seems not a necessary concept.

Ah, this is rejected by Mahayana buddhism (and I think Thervada too) as can easily be seen in the allegory of the chariot by Chandrakirti. This can be found also in this sutta.

Or does Buddhism never have an answer for such question as it belongs
to papañca (conception proliferation) and thus effectively reject true
possibility of exact mental appearances sharing?

What do you mean by &quot;exact&quot; here? I would challenge you to find even one set &quot;thing&quot; in this world or any other in which all beings immediately agree or have a universal objective experience that does not differ in any significant way. Name one such universal qualia that is permanent and fixed. Can you?
I'm not sure if these allegories help answer your questions, but your questions aren't very specific. Rather they seem to allude to a whole host of ideas that are not well defined and mixing western philosophical words/ideas - that are themselves ill-defined - with Buddhist ideas that may/may not be defined according to your usage. Anyway, I hope it is helpful.