瑜伽師地論略纂 15.34

15.34

色界有鼻、舌界，云「又色界中，於此二種未離欲」者，謂外愛斷故，無香、味；香、味無故，二識亦無。若有識，必緣境生。此二緣外愛生，內愛未斷，故二界有。

The form realm possesses the nose and tongue elements; regarding the statement, 'Furthermore, in the form realm, one has not detached from desire regarding these two': it means that because external craving has been severed, there are no smell and taste; because smell and taste do not exist, the two consciousnesses also do not exist. If there is consciousness, it must arise by taking an object. These two arise by relying on external craving, but internal craving has not yet been severed; hence the two elements exist.