What is evil to thee does not subsist in the ruling principle of another; nor yet in any turning and mutation of thy corporeal covering. Where is it then? It is in that part of thee in which subsists the power of forming opinions about evils. Let this power then not form such opinions, and all is well. And if that which is nearest to it, the poor body, is burnt, filled with matter and rottenness, nevertheless let the part which forms opinions about these things be quiet, that is, let it judge that nothing is either bad or good which can happen equally to the bad man and the good. For that which happens equally to him who lives contrary to nature and to him who lives according to nature, is neither according to nature nor contrary to nature.
About what am I now employing my own soul? On every occasion I must ask myself this question, and inquire, what have I now in this part of me which they call the ruling principle? And whose soul have I now? That of a child, or of a young man, or of a feeble woman, or of a tyrant, or of a domestic animal, or of a wild beast?
The ruling principle is that which rouses and turns itself, and while it makes itself such as it is and such as it wills to be, it also makes everything which happens appear to itself to be such as it wills.
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.