Meditations 4:4

If thought is something we share, then so is reason—what makes us reasoning beings.

If so, then the reason that tells us what to do and what not to do is also shared.

And if so, we share a common law.

And thus, are fellow citizens.

And fellow citizens of something.

And in that case, our state must be the world. What other entity could all of humanity belong to? And from it—from this state that we share—come thought and reason and law.

Where else could they come from? The earth that composes me derives from earth, the water from some other element, the air from its own source, the heat and fire from theirs—since nothing comes from nothing, or returns to it.

So thought must derive from somewhere else as well.