Nearly every word involving the kanji 可 in Japanese has something to do with permission: impossible (不可能), possible (可能), permission (許可), approval (可決), etc.
That said, the kanji-centric view of the world is ineffective, and one primarily adopted by beginner learners who have not spent any significant amount of time studying words in Japanese. It is always better to just learn words.
Sure, didn't I say they were in my post?
The point was, in a discussion of how well X predicts Y, it's not very useful to examine a test case where Y came first and X was chosen post-hoc to match it.
No, quite the opposite actually ;)
I do take your point that using that word in the discussion above, which is about Japanese was not the best example. On the other hand, it is a good example in chinese.
(B) By arbitrary here I mean that there is no linguistic connection. "Arbitrarily chosen because they are similar" => "chosen for no reason other than their similarity".
In this case, though it does seem that the characters where chosen at least partly because of their actual meaning.
It seems that it is both an ateji and a jukujikun [1] because the word does not come from the characters but the characters do have the correct meaning.
[1]https://en.wiktionary.org/wiki/%E5%8F%AF%E6%84%9B%E3%81%84#J...