俱舍論疏 2.27

2.27

論「若爾至段食性故」，第二問答分別也。香、味是段食性，上界無段食，故無香、味境。觸界亦段食性，色界應無。

The treatise says: "If so... because its nature is material food." This is the second [part], analysis through questions and answers. Smell and taste have the nature of material food, and since the higher realm lacks material food, it therefore lacks the objects of smell and taste. The tactile dhātu also has the nature of material food, so the form realm should lack it as well.