俱舍論疏 15.147

15.147

論「有餘師說至異熟果故」，敘異說也。此師意說：三禪已下亦有順不苦不樂受業，以中間定唯不苦不樂受故，彼定所招唯自地故，故知唯能招順、非二受。若異此者，此中間定應無異熟，即違不善、善有漏定是異熟因也。或應無業者，中定既有意思，不可無業，故知定有順、非二業。

The Śāstra says: "Other masters say [...] because it is the fruit of vipāka." This presents a divergent view. This master's intention is: below the third dhyāna there is also karma conducive to neither-painful-nor-pleasant feeling, because intermediate dhyāna is exclusively neither-painful-nor-pleasant feeling, and what that absorption brings about belongs exclusively to its own level; thus we know it can only bring about feeling conducive to neither of the two. If it were otherwise, this intermediate dhyāna would have no vipāka, which would contradict the rule that unwholesome and good contaminated absorptions are causes of vipāka. Or, if it is said that it would lack karma: since intermediate dhyāna possesses mental volition, it cannot lack karma; hence we know there is definitely karma conducive to neither of the two.