首楞嚴義疏注經 3.254

3.254

破根生也。觀對待也，無二所覺為相待緣，獨此身根無生識理。下破境生。

This refutes production from the faculty. 'Observation' means mutual relativity: without the two perceived objects serving as mutually relative conditions, this body faculty alone has no reason to produce consciousness. Below refutes production from the object.