首楞嚴義疏注經 3.146

3.146

破轉救也。初二句牒救總徵。若汝救云：所生雖一，能生自二，云何令我頭手不異者，此則一體之觸為在何處？故云觸誰為在。在能下二句推同前破，前云若在於手，頭則無用等。不應下破空生也，有形之法尚不能生，豈況空無而能成觸。

Refuting the shifted defense. The first two lines cite the defense and question it generally. If you defend by saying: 'Although that which is produced is one, those that produce it are naturally two; why force my head and hand not to be different?'—then where does this single touch reside? Hence it says: 'In which would the touch reside?' The two lines from 'if it resides in the agent' deduce the same refutation as before; previously it said, 'If it is in the hand, the head would have no function,' and so forth. From 'nor can' onward refutes its being born from space: even dharmas with form cannot produce it, how much less could empty nonexistence accomplish touch?