首楞嚴義疏注經 10.98

10.98

此有無俱計也。其境枝故其心亦亂者，以不定是一義，故成亂也。以前二論但偏證有無，今此一論即有無俱見也。亦有即是亦無者，意計亦有之中即有於無，得成有無計也。亦無之中不是亦有者，雖於有中說無，二相各別，故云不是亦有。無容窮詰者，若詰有即是無，又云無中不是亦有；若詰無不是有，又云亦有即是亦無。互相遮防，故難窮詰。

This is calculating both existence and nonexistence. 'Because his cognitive objects branch off, his mind also becomes confused': because it is not definitely a single meaning, confusion ensues. The previous two doctrines merely biasedly verified existence or nonexistence; now this one doctrine sees both existence and nonexistence together. 'Both existing is itself both nonexisting': he internally calculates that within both existing there is nonexistence, thus establishing the calculation of existence and nonexistence. 'Within both nonexisting, it is not both existing': although he speaks of nonexistence within existence, their two characteristics are distinct, hence he says 'it is not both existing'. 'Admitting of no exhaustive questioning': if questioned on existence being nonexistence, he again says that within nonexistence it is not both existing; if questioned on nonexistence not being existence, he again says that both existing is itself both nonexisting. They mutually ward off and defend, hence it is difficult to question exhaustively.