As To Living In the Best Way
As to living in the best way, this power is in the soul, if it be indifferent to things which are indifferent. And it will be indifferent, if it looks on each of these things separately and all together, and if it remembers that not one of them produces in us an opinion about itself, nor comes to us; but these things remain immovable, and it is we ourselves who produce the judgments about them, and, as we may say, write them in ourselves, it being in our power not to write them, and it being in our power, if per chance these judgments have imperceptibly got admission to our minds, to wipe them out; and if we remember also that such attention will only be for a short time, and then life will be at an end. Besides, what trouble is there at all in doing this? For if these things are according to nature, rejoice in them and they will be easy to thee: but if contrary to nature, seek what is conformable to thy own nature, and strive towards this, even if it bring no reputation; for every man is allowed to seek his own good.
Marcus Aurelius, in 'Meditations'