Autarky. Marcus Aurelius 4.13

Reason solves problems, but like any solvent it can be dangerous. Make sure to taste your own reason's medicine, to avoid spreading it too liberally or carelessly beyond the realm that is yours. Never try to solve for others what can only be solved by the self.

«Λόγον ἔχεις;» «ἔχω.» «τί οὖν οὐ χρᾷ; τούτου γὰρ τὸ ἑαυτοῦ ποιοῦντος τί ἄλλο θέλεις;»

Q. "Have you a faculty for rational judgement?" A. "I do." Q. "Why then do you not use it? If it is already employed looking after itself, what more do you want?"