Meditation 2.15-16
15. 'Everything is what you judge it to be.' While the retort made to the Cynic philosopher Monimus is plain enough, plain too is the use of the saying, if one only take the gist of it, so far as it is true.
16. The soul of a man does violence to itself, first and foremost when it becomes so far as in it lies, a separate growth, a blain as it were upon the Universe. For to turn against anything that comes to pass is a separation from Nature, by which the natures of each of the rest are severally comprehended. Secondly, when it turns away from any human being or is swept counter to him, meaning to injure him, as is the case with the natures of those who are enraged. It violates itself, thirdly, when it is the victim of pleasure or pain; fourthly, when it acts a part, and says or does anything both feignedly and falsely. Fifthly, when, failing to direct any act or impulse of its own upon a mark, it behaves in any matter without a plan or conscious purpose, whereas even the smallest act ought to have a reference to the end. Now the end of reasonable creatures is this: to obey the rule and ordinance of the most venerable of all cities and governments.