So, we have the kanji 上・下 which can be read as either かみ・しも or うえ・した, and as I understand it, those two are antonym pairs. But what are the differences between the two?
The thesaurus isn't very helpful. For instance, it says, for うえ
何かとくらべて高い方の位置、場所。
and for かみ it says
位置が高いこと。また、ひと続きのものの初め。川では上流、和歌などでは前半をいう。
If I understand this correctly, this is saying that うえ is simply the place or position above some reference level, while かみ is the state of being above, or the start of a series. But the dictionary entry for かみ goes on to give definitions like
位置の高い所。
which bring it right back into the territory of うえ, or at least very close. It almost looks like the distinction is supposed to be relative vs absolute, but this just confuses me since, at least in my mind, above/below are inherently relative.
Question. What are the differences between かみ・しも and うえ・した? Are there minimal pairs illustrating these differences?