Book IX · 15
Things stand outside of us, themselves by themselves, neither knowing aught of themselves, nor expressing any judgment. What is it, then, which does judge about them? The ruling faculty.
Objective things stand outside the door, keeping themselves to themselves, without knowledge of or message about themselves. What then has for us a message about them? The ruling Reason.
Marcus Aurelius, Meditations IX.15. Translated by George Long (1862). The Stoic Library.