瑜伽師地論略纂 14.21

14.21

論云一切色乃至觸，二識所識中云「或漸或頓」者，謂隨一五識中識起，意與俱緣，名漸；若五識並生，意亦同緣，名為頓。

The treatise says, regarding all matter up to tangibles being cognized by two consciousnesses, that it is "either gradual or simultaneous": this means that when any single consciousness among the five consciousnesses arises, and mental consciousness cognizes together with it, this is called gradual; if the five consciousnesses arise side by side, and mental consciousness also cognizes identically, this is called simultaneous.