首楞嚴義疏注經 2.207

2.207

此破轉計也。汝若執言：我亦見佛不見之體，復有何失？故云若見不見。即便破云：自然非彼不見之相，意云：不見之體既被汝見，此則何成不見之相？不見之體已被見故。

This refutes the shifted calculation. If you cling to the claim: 'I also see the entity of the Buddha's not-seeing, so what fault is there?' Hence it says, 'If you do see my not-seeing.' It then immediately refutes it: 'it is naturally not that mark of not-seeing.' The meaning is: since the entity of not-seeing is seen by you, how can this constitute the mark of not-seeing? For the entity of not-seeing has already been seen.