[causi]

This feels like a "god of the gaps" religious argument. Every time we learn more the degree to which two people's perception of color can vary shrinks as we find them functionally identical at every level of our understanding. Will it take the invention of a machine that can perfectly read a human's mind to convince armchair philosophers there are no more shadows for it to hide in?

[ag315]

Your analogy doesn't work and I suspect it's because you may fundamentally misunderstand what qualia actually are--this isn't about gaps; this relates much more to the logical impossibility of reducing qualia to something that can be understood through quantitative methods. You dropped the key in the dark and are looking for it under a beam of light three feet away by trying to claim that any any amount of neuroscience could answer a question of this nature.

That said, much like the problem of induction, its insolubility is not necessarily of much practical importance day-to-day. We know that certain wavelengths will be recognized by people with normal visual faculties as "red"; whether the way they experience that qualia is different or not is not of much practical importance. It's more of a reminder of the limits of our empirical knowledge.

[causi]

What is the difference between something that is undefinable and something that is fictitious?