They understand: ‘When my body breaks up and my life has come to an end, everything that’s felt, since I no longer take pleasure in it, will become cool right here. Only bodily remains will be left.’
SN 12.51 is interesting as the phrase ‘sarīrāni avasissantīti pajānāti’ seems to be the one that you’ve bolded? From what I can tell the parallels for this sutta do not contain this statement or an equivalent, but I may be wrong as I’m no expert in either language. Also interesting is that the three translations into english are different:
Only bodily remains will be left. → sujato
Mere bodily remains will be left. → bodhi
While the corpse will remain. → thanissaro
As I’m no expert in Pali I can’t ascertain which is correct, but the first seems the one that can be read most clearly to imply a dichotomy. The other half of that dichotomy from the context seems to be life? It seems to be stating that life utterly ceases in contrast to the bodily remains.
As for the parallels…
The parallel - SA 292 - does not seem to contain this statement of the body remaining in contrast to life. The simile of the hot pot that cools exists so that would indicate a clear parallel. @cdpatton can you verify this is the case?
The other parallel is SF 159 which also contains the simile of the hot pot that cools and it too is missing any reference to the body remaining in contrast to life. Rather, it seems to relate just a hot pot that cools when placed on the ground as a simile for the ending of life.
I also can’t find the specific pali words repeated anywhere else… Are there any other suttas/abhidhamma/commentary/other which express this categorical dichotomy between form and mind as the former decaying while the latter utterly disappears in a single moment?
All too soon this body
will lie upon the earth,
bereft of consciousness,
tossed aside like a useless log.
That says pretty clearly that a body does not possess consciousness at some point after life has ended. It doesn’t speak about whether that consciousness decays and breaks down in the body or elsewhere or disappears in a single moment though does it?
It’s true that the passage doesn’t explicitly say the body remains after death, but I would say it’s implied. The heated pot is a metaphor for a living person. The body cools after death like the pot, and the pot shattering is like the expression that the body breaks up. So, I would say the Pali has added an obvious detail that’s left unsaid.
Does it refer to the pot shattering or is it just placed on the ground? I think the other parallel does not refer to it shattering and doesn’t speak of shards?