肇論新疏 2.203

2.203

何者？夫聖心虛靜，無知可無，可曰無知，非謂知無。惑智有知，故有知可無，可謂知無，非曰無知也。

Why so? The sage mind is vacuous and tranquil, with no knowing that could be negated; it can be called "without knowing," but is not said to "know non-being." Deluded wisdom possesses knowing, and therefore there is knowing that can be negated; it can be called "knowing non-being," but is not said to be "without knowing."