俱舍論頌疏論本 2.11

2.11

Those bound to the formless realm are only the last three, namely the mind-dhātu, mental consciousness dhātu, and dharmadhātu. The five faculties such as the eye, and the five objects such as visible form—these ten are material. The formless realm is free from matter, and therefore lacks these ten. Because it lacks these ten, the five consciousnesses are also absent. Hence the treatise says: "Because their supports and conditions are absent, the five consciousnesses are also absent (the five faculties are the supports, and the five objects are the conditions)." Therefore only the last three are bound to the formless realm.