Knowledge is of value only as a tool of the good life. “What, then, can direct a man? One thing only- philosophy”- not as logic or learning, but as a persistent training in moral excellence. “Be thou erect, or be made erect.” God has given every man a guiding daimon, or inner spirit- his reason. Virtue is the life of reason.

These are the principles of the rational soul. It traverses the whole universe, and surveys its form, and extends itself into the infinity of time, and embraces the cyclical renewal of all things, and comprehends that those who come after us will see nothing new, nor have those before us seen anything more; but in a manner he who is forty years old, if he has any understanding at all, has seen, by virtue of this uniformity, all things that have been or will be.

Marcus thinks his premises compel him to puritanism. “Pleasure is neither good nor useful.” He renounces the flesh and all its works, and talks at times like some Anthony in the Thebaid:

Observe how ephemeral and worthless human things are, and what was yesterday a little mucus, tomorrow will be a mummy or ashes…. The whole space of man’s life is but little, and yet with what troubles it is filled… and with what a wretched body it must be passed!… Turn it inside out, and see what kind of thing it is.

The mind must be a citadel free from bodily desires, passions, anger, or hate. It must be so absorbed in its work as hardly to notice the adversities of fortune or the barbs of enmity. “Every man is worth just so much as the things about which he busies himself.” He reluctantly concedes that there are bad men in this world. The way to deal with them is to remember that they, too, are men, the helpless victims of their own faults by the determinism of circumstance. “If any man has done thee wrong, the harm is his own; it is thy duty to forgive him.” If the existence of evil men saddens you, think of the many fine persons you have met, and the many virtues that are mingled in imperfect characters. Good or bad, all men are brothers, kinsmen in one God; even the ugliest barbarian is a citizen of the fatherland to which we all belong. “As Aurelius I have Rome for my country; as a man, the world.” Does this seem an impracticable philosophy? On the contrary, nothing is so invincible as a good disposition, if it be sincere. A really good man is immune to misfortune, for whatever evil befalls him leaves him still his own soul.

Will this [evil] that has happened prevent thee from being just, magnanimous, temperate, prudent… modest, free?… Suppose that men curse thee, kill thee, cut thee in pieces: what can these things do to prevent thy mind from remaining pure, wise, sober, and just? If a man stand by a limpid, pure spring and curse it, the spring never ceases to send up clean water; if he cast dirt into it, or filth, it will speedily wash them out and be unpolluted again…. On every occasion that brings thee trouble, remember to apply this principle: that this is not a misfortune, but that to bear it nobly is good fortune…. Thou seest how few the things are to which if a man lays hold of, he is able to live a life that flows on quietly and is like the existence of the gods.