首楞嚴義疏注經 2.296

2.296

先答不知也，何以下釋不知所以。若也樹不是見，應離能見之外見所不及，云何現今復見於樹？又若此樹即是於見，云何更名此以為樹？空例此釋。離之既不可，即之又難明，進退研之，未知所適。

First he answers that he does not know; 'Why?' introduces the explanation of the reason for not knowing. If a tree were not seeing, it should be apart from that which can see, beyond the reach of seeing; how could one now see the tree? Furthermore, if this tree were precisely seeing, how could one still call it a tree? Space is explained analogously to this. Separation from it is impossible, yet identity with it is difficult to elucidate; investigating forward and backward, he does not know where to stand.