成唯識論演祕 2.716

2.716

前有法言能取彼覺，後法復言亦不緣彼，既言能取何不緣彼？既不緣彼何名能取？故成相違。量標汝言，故無斯咎。

The subject earlier states that the cognition grasps that, but the predicate later says that it also does not cognize that as an object. Having said that it grasps it, how could it not take it as an object? Since it does not take it as an object, how could it be called grasping? Thus it would become a contradiction. In the formal syllogism (prayoga), one specifies "according to you," so there is no such fault.