Regarding Lang’s questions above:
Yes. There is a difference between “Arahant phala samāpatti” and “nirōdha samāpatti“.
– In “Arahant phala samāpatti” citta can flow, but they are TOTALLY uncontaminated. Thoughts are in the first stage of the nine-stage evolution of “citta, manō, mānasan, hadayaṃ, pandaran, manō manāyatanam, mana indriyam (or manindriyam), viññāna, viññānakkhandha“.
See, “Amazingly Fast Time Evolution of a Thought (Citta)”
– On the other hand “nirōdha samāpatti” is like what happens AFTER Parinibbana. Absolutely no citta.
To complete the story, a living Arahant’s citta gets to the third stage of citta evolution, the “mānasan” stage. That is why a living Arahant can RECOGNIZE a person as mother, father, a beautiful woman, etc.
– But since it does not get to the “hadayaṃ” stage, the Arahant would have no special attention for mother or ANY attraction to a beautiful woman versus an ugly woman.
– So, the citta of a living Arahant does not even get to the “hadayaṃ” stage let alone to the viññāna stage.
– An Arahant in Arahant phala samāpatti is just AWARE that he/she is alive. He/she will not even experience ANY external arammana. He/she will not see, hear, anything. There is a sutta that describes the following situation. The Buddha was in Arahant phala samāpatti once, and lightning struck and killed a couple of people closeby. A large crowd of people came to see that and the Buddha was not aware of it until he came out of Arahant phala samāpatti.
– I recommend reading the post referred above.
The NON-REVERSIBLE cooling down (“niveema”) happens in stages. First is at the “Sotapanna Anugami” stage when one starts comprehending Tilakkhana. Then it is completed at the Arahant stage.
– Of course, there is “cooling down” or ‘niramisa sukha” even before the “Sotapanna Anugami” stage, but that is reversible. If one, later on, starts moving away from the path (mostly due to external influences), then it may be lost.
Yes. Nirōdha samāpatti is the closest to the state of an Arahant after Parinibbāna. No flow of cittā.