Could the beetle in the box not play any role in our…?Or will the similar neurological constituents and the same physical input provide some supports to the "pain",in a (Kantian) way that each person has her own sense perception but is similar to each other,or at least has the same scheme?
Wittgenstein's "beetle in a box" argument is easily seen to be incorrect, simply by our successful operation of internal dialog and reasoning processes, and that we succeed with both even as prelingual toddlers. His presumption that we would no longer be able to reason or think to ourselves, if the rest of humanity died out and we could no longer confirm word meanings with an external community, is implausible in the extreme.
Are there some kinds of arguments in defense of Private Language?
Well consider the case of a space where all speech acts are public.
Q. How then can one carry out a private conversation?
Because its due to conversations being private that one can plan to ones advantage, and to the disadvantage of others (and in this case, mostly to others; in the sense, the others are more numerous).
Well, in such a public space, one invents a private language. That looks like the public language, but is so coded that one knows what is being said. If you have some physics knowledge, think of a communication signal being overlayed on a carrier wave.
Note however, the advantage is accrued wholly to the private group, who are in charge of the private language. Thus, if you are publicly minded, you might think this is no advantage at all; and in fact, a disadvantage.
So I came to praise private language, and in fact, it seems I have buried it...!