俱舍論記 28.59

28.59

「立第四名至是立名正因」者，釋後無色立第四名由想昧劣。謂無下七地，明勝想故，得非想名。有昧劣想故，不同二無心，名非非想。雖加行時亦作是念：前七定諸想如病、如箭、如癰。或初、二定喜想如病，三定樂想如箭，四、五、六、七地捨想如癰。若想全無如二無心，便同愚癡黑闇相似，無所覺知。唯有非想非非想中與上相違，寂靜美妙。於加行中厭想厭無想，應名非想非非想，而不就此加行立名。以若詰言：何緣加行作如是念？必應答言：以於彼有頂根本處想昧劣故，所以加行隨彼根本作如是念。由此根本想昧劣故，是立非想非非想名正因，故從根本立名，不從加行立名。又《正理》云「此四無色皆言處者，以是諸有生長處故。」

Regarding 'Establishing the fourth name... is the direct cause of establishing the name': this explains that establishing the fourth name for the last formless state is due to its ideation being obscure and weak. Because it lacks the clear and superior ideations of the lower seven stages, it obtains the name 'neither ideation'; because it has obscure and weak ideation, differing from the two mind-less states, it is called 'nor non-ideation'. Although at the time of preparatory practice one also thinks: 'The ideations of the preceding seven absorptions are like a disease, like an arrow, like a boil.' Or, 'The ideation of joy in the first and second absorptions is like a disease, the ideation of pleasure in the third absorption is like an arrow, and the ideation of equanimity in the fourth, fifth, sixth, and seventh stages is like a boil. If there were entirely no ideation, as in the two mind-less states, one would resemble the darkness of ignorance, devoid of awareness. Only in neither ideation nor non-ideation is it contrary to the above, tranquil and exquisite.' In the preparatory practice, cultivating aversion toward ideation and aversion toward non-ideation should yield the name 'neither ideation nor non-ideation', yet the name is not established based on this preparatory practice. For if one were asked, 'For what reason does the preparatory practice produce such a thought?', one must answer: 'Because in the fundamental state of the peak of existence ideation is obscure and weak, the preparatory practice produces such a thought in conformity with that fundamental state.' Because ideation in this fundamental state is obscure and weak, this is the direct cause of establishing the name 'neither ideation nor non-ideation'; thus the name is established from the fundamental state, not from the preparatory practice. Furthermore, the Nyāyānusāra says: 'The reason these four formless states are all called "bases" (āyatana) is that they are the places of growth and arising of existences.'