大乘百法明門論開宗義決 1.37

1.37

深密等經為不了義等者。謂此宗中以三無性為真了義。遣三性故即說三性體不可得。依計所執立想無性。顯計所執即無體相。依自依他立生無性。如何但無自然生性。勝義無性當知亦然。故深密等建立三性。有所存故非了義也。

Regarding "the Sandhinirmocana and other sūtras are teachings of provisional meaning," etc.: This means that in this school, the three non-natures are considered the true definitive meaning. Because the three natures are eliminated, it is said that the substance of the three natures is unobtainable. Relying on the imaginary [nature] (parikalpita), the non-nature of characteristics is established, revealing that the imaginary lacks substance and characteristics. Relying on the other-dependent [nature] (paratantra), the non-nature of production is established—how could there merely be no naturally occurring nature of production? The non-nature of ultimate truth should also be known to be likewise. Therefore, when the Sandhinirmocana and others establish the three natures, because there is something retained, they are not of definitive meaning.