肇論新疏 2.115

2.115

謂般若之體無知無見，亦非是無；有鑒有靈，亦非是有。非有下，但躡前，釋成知與無知非一非異，方詺中道之心。

This means that the essence of prajñā is without knowing and without seeing, yet it is also not non-existent; it possesses mirror-like illumination and numinous awareness, yet it is also not existent. From "because it is not existent..." onward: this merely follows the preceding to explain that knowing and being without knowing are neither one nor different, only then designated as the mind of the Middle Way.