My question, though, was why you were pretty sure that it was for permanent versus impermanent things. I've heard a number of people say that, but I've never seen anyone explain who told them that, or what textbook they got it from, so I just wondered where that idea came from, and whether there was a more formal expression of this "rule".
Unless it was from a teacher who really didn't want to explain the difference between a noun and an adjective, the permanent/impermanent distinction seems to break down a lot (as in this sentence).
In Irish, you respond to a question by repeating the verb. The positive response to an an bhfuil? question is Tá., and the negative response is Níl.
An bhfuil sé marbh? - Níl. Tá sé beo!!
'Sea/Is ea and Ní hea are responses to the interrogative form of the copula: An (noun) é? - Ní hea.