首楞嚴義疏注經 1.408

1.408

無者不在也。若此決定不著諸法，何處是心名為不著，便同世間龜毛兔角畢竟無體。體既全無，而欲名誰為不著耶！

'Non-existent' means not located. If it is definitively unattached to all dharmas, where is the mind that is called unattached? It would then be the same as worldly tortoise hair and hare's horns, which completely lack substance. Since substance is entirely absent, whom would one wish to call unattached?