大乘百法明門論開宗義決 1.91

1.91

小乘通依三世眼等者。眼等六識但在未來皆名為心。由未取境但體積集當生起故。隨其一識緣會之時流至現在乃名為識。有了別用名為識故。若起用已滅入過去即名為意。能與後念作無間緣開避引導名意根故。

Regarding "the Hīnayāna generally relies on the eye, etc., across the three periods of time": As long as the six consciousnesses, such as the eye [consciousness], are in the future, they are all called "citta"; because they have not yet apprehended objects, they are merely an accumulation of entities that are to arise. When any one consciousness meets its conditions and flows into the present, it is then called "vijñāna" (consciousness); because it has the function of cognizing, it is called vijñāna. When it has produced its function, ceases, and passes into the past, it is called "manas" (mind); because it can serve as the immediately antecedent condition (samanantara-pratyaya) for subsequent moments, clearing the way and guiding, it is called the manas faculty (manendriya).