成唯識論述記 4.449

4.449

述曰：此食通與八識相應故。雖通與八識相應，屬意識者食義偏勝，故《瑜伽》說：深勝希望及緣未來，非餘俱思，希望勝故。由此亦准，屬六識者體非六識，不爾思食體應第六。問：欲何故不為食體，而取俱思？答：思慮益根，非欲能故。

The Commentary states: This is because this nutriment is conjoined throughout with the eight consciousnesses. Although it is conjoined throughout with the eight consciousnesses, that which belongs to the mental consciousness has a predominantly superior sense of nutriment. Therefore the Yogācārabhūmi says: it has profound and superior hoping and takes the future as its object; it is not the volition conjoined with the others, because its hoping is superior. By this it can also be inferred that what belongs to the six consciousnesses is not identical in substance with the six consciousnesses; otherwise, the substance of the nutriment of volition would have to be the sixth consciousness. Question: Why is desire not taken as the substance of nutriment, but rather the conjoined volition? Answer: Deliberation benefits the faculties, whereas desire cannot do so.