Meditations 7.55

Do not look around thee to discover other men's ruling principles, but look straight to this, to what nature leads thee, both the universal nature through the things which happen to thee, and thy own nature through the acts which must be done by thee. But every being ought to do that which is according to its constitution; and all other things have been constituted for the sake of rational beings, just as among irrational things the inferior for the sake of the superior, but the rational for the sake of one another.

The prime principle then in man's constitution is the social. And the second is not to yield to the persuasions of the body,—for it is the peculiar office of the rational and intelligent motion to circumscribe itself, and never to be overpowered either by the motion of the senses or of the appetites, for both are animal: but the intelligent motion claims superiority, and does not permit itself to be overpowered by the others. And with good reason, for it is formed by nature to use all of them. The third thing in the rational constitution is freedom from error and from deception. Let then the ruling principle holding fast to these things go straight on, and it has what is its own.

Marcus Aurelius, Meditations 7.55, translated by George Long

Look not about thee at the ruling Reason of others, but look with straight eyes at this, To what is Nature guiding thee?—both the Nature of the Universe, by means of what befalls thee and thy nature by means of the acts thou hast to do. But everyone must do what follows from his own constitution; and all other things have been constituted for the sake of rational beings—just as in every other case the lower are for the sake of the higher—but the rational for their own sake.

Social obligation then is the leading feature in the constitution of man and, coming second to it, an uncompromising resistance to bodily inclinations. For it is the privilege of a rational and intelligent motion to isolate itself, and never to be overcome by the motions of sense or desire; for either kind is animal-like. But the motion of the Intelligence claims ever to have the pre-eminence and never to be mastered by them. And rightly so, for it is its nature to put all those to its own use. Thirdly, the rational constitution is free from precipitancy and cannot be misled. Let the ruling Reason then, clinging to these characteristics, accomplish a straight course and then it comes into its own.

Marcus Aurelius, Meditations 7.55, translated by C. R. Haines