俱舍論記 28.179

28.179

「同諸近分至苦通行攝」者，釋捨受。此中間定同諸近分，唯捨相應非喜相應，由自勉勵功用轉故，由此說是苦通行攝。亦無有樂，無三識故。故《正理》云「無三識身，故無樂受。」准《正理》文，中定無三識。問：何故無耶？解云：五識定與尋、伺相應，彼無尋故。

"Like all the preliminary stages […] subsumed under the painful path of practice" explains equanimity feeling. This intermediate concentration, like all the preliminary stages, is associated solely with equanimity and is not associated with joy, because it operates through self-exertion and effort; due to this, it is said to be subsumed under the painful path of practice (duḥkhā pratipad). It also lacks pleasure, because it lacks the three consciousnesses. Hence the Nyāyānusāra says: "Because it lacks the three consciousness-bodies, it lacks pleasant feeling." According to the text of the Nyāyānusāra, the intermediate concentration lacks the three consciousnesses. Question: Why are they absent? The explanation says: The five consciousnesses are necessarily associated with coarse examination and subtle investigation, whereas that [intermediate state] lacks coarse examination.