And here, my dear Glaucon, is the supreme peril of our human state; and therefore the utmost care should be taken. Let each one of us leave every other kind of knowledge and seek and follow one thing only, if peradventure he may be able to learn and may find some one who will make him able to learn and discern between good and evil, and so to choose always and everywhere the better life as he has opportunity.
He should consider the bearing of all these things which have been mentioned severally and collectively upon virtue; he should know what the effect of beauty is when combined with poverty or wealth in a particular soul, and what are the good and evil consequences of noble and humble birth, of private and public station, of strength and weakness, of cleverness and dullness, and of all the natural and acquired gifts of the soul, and the operation of them when conjoined. He will then look at the nature of the soul, and from the consideration of all these qualities he will be able to determine which is the better and which is the worse.
And so he will choose, giving the name of evil to the life which will make his soul more unjust, and good to the life which will make his soul more just; all else he will disregard. For we have seen and know that this is the best choice both in life and after death.
A man must take with him into the world below an adamantine faith in truth and right, that there too he may be undazzled by the desire of wealth or the other allurements of evil, lest, coming upon tyrannies and similar villainies, he do irremediable wrongs to others and suffer yet worse himself; but let him know how to choose the middle way and avoid the extremes on either side, as far as possible, not only in this life but in all that which is to come. For this is the way of happiness.