俱舍論疏 28.139

28.139

論「由此可說至不說想等」，經部就自宗釋也。由初定中立尋、伺、喜、樂受支故，減前支故立後靜慮，即由此理初說五支。減初尋、伺立第二定，減其喜受并尋伺三立第三定，減其樂受并前三支立第四定。想等無減，故不立支。

On the Śāstra's phrase: "From this it may be said [...] not mentioning ideation and so forth": the Sautrāntika explains according to its own school. Because the factors of vitarka, vicāra, joy, and bliss are established in the first dhyāna, the subsequent dhyānas are established by reducing previous factors; it is precisely through this principle that five factors are initially stated. By reducing the initial vitarka and vicāra, the second dhyāna is established; by reducing its sensation of joy together with vitarka and vicāra—these three—the third dhyāna is established; by reducing its sensation of bliss together with the previous three factors, the fourth dhyāna is established. Because ideation and so forth are not reduced, they are not established as factors.