Full Idea
One whose thoughts are truly directed to the things that are …looks at and studies things that are organised and always the same, that neither do injustice to one another nor suffer it, being all in a rational order.
Gist of Idea
The true reality is organised and harmonised in a rational order
Source
Plato (The Republic [c.371 BCE], 500c)
Book Reference
Plato: 'Complete Works', ed/tr. Cooper,John M. [Hackett 1997], p.1121
A Reaction
I take this to be the source of the belief of the Stoics (and later of Frege) that nature has an intrinsic rational order, which our intellect can grasp with discipline and training. The idea starts, of course, with Pythagoras. The Forms have structure.