Maybe I’m misreading your tone, but I’m not trying to argue with you - I’m genuinely curious about this and if you have superior knowledge I’m open!
My understanding from a quick skim of Wikipedia citations suggests we understand what’s involved (particles and receptors) but the actual mechanism around encoding of signals seems to be theory.
We also can’t teach a computer to think, but we still have quite a good idea of how it works.
I can understand someone not wanting their kids to see the Scottish. But the English and the Welsh? Those people live SOUTH of the wall.