肇論新疏 2.211

2.211

何者？內有獨鑑之明，外有萬法之實，萬法雖實，然非照不得。內外相與以成其照功，此則聖所不能同用也。

Why so? Within, there is the clarity of solitary reflection; without, there is the reality of the myriad dharmas. Although the myriad dharmas are real, without illumination they cannot be attained. Within and without mutually assist to accomplish their efficacy of illumination; this, then, is where the sage cannot make their functions identical.