Book 9 of the Nicomachean Ethics explores the nature of friendship in great detail. It is in the context of this wider focus that Aristotle devotes five paragraphs in the eighth section to the subject of self-love.
The two notions of self-love may be defined as such: the good man's love of self and the bad man's love of self. The discussion below will trace the progression of Aristotle's ideas, which take an indirect path, but foregrounding the main points may prove helpful at this point. In short, Aristotle argues that self-love in itself is neither good nor bad in itself; however, a bad man's self-love deserves reproach, while the self-love of a good, virtuous man is praiseworthy. Naturally, the self-love of a bad man is undesirable and something to be avoided.
The opening paragraph of section eight introduces the theme of self-love in relation to the broader discussion on friendship that fills the preceding seven sections of book 9. Aristotle observes that self-love is generally viewed with reproach. A self-lover is looked down upon as a disgrace for loving himself above all other persons and things. While such unsavory forms of self-love do exist, Aristotle associates them with the attitudes and behavior of wicked people, and he cautions against branding all forms of self-love as undesirable.
A key point in this paragraph concerns the initial distinction made between the bad man and the good man, even though the significance of the opposition is yet to be fleshed out.
Before proceeding with the question about self-love as an object of reproach, Aristotle turns in paragraph two to a seemingly tangential matter concerning a pair of contrary views: first, that a person should love best oneself, and second, that a person should love best one's best friend. He resolves the conflict by suggesting that a man who loves his best friend thus loves himself as well and qualifies as a lover of self.
Next, Aristotle explains why self-love is commonly viewed with contempt. The reproach is warranted in most cases of self-love because they tend to betray the self-lover grasping for unearned reward. Self-lovers warrant censure for seeking to "gratify their appetites and in general their feelings and the irrational element of the soul."
Aristotle then shifts direction in the final sentence of the third paragraph. At the tail end of a passage validating in detail the common reproachful view of self-love, Aristotle drains its momentum by pointing to a form of self-love that does not fit into the mold he has been describing. The turn occurs with subtlety, however. He writes,
if a man were always anxious that he himself, above all things, should act justly, temperately, or in accordance with any other of the virtues, and in general were always to try to secure for himself the honourable course, no one will call such a man a lover of self or blame him.
What Aristotle means is that certain traits universally praised are not called examples of self-love because self-love is so often—and mistakably—regarded as unpraiseworthy.
The fourth paragraph of section eight features the heart of the argument. Aristotle underscores the variable forms of self-love, insisting that there is a form of self-love that merits no reproach. That is the good man's love of self, which amounts to his deliberately pursuing righteousness, justice, and virtuous living. Clearly, such a man seeks those good and desirable things for the sake of his own well being, but in doing so he also becomes a benefit to the common good.
The closing paragraph of the section shows Aristotle advancing his carefully set-up argument about self-love. The good man must have self-love, but on the other side of the coin, the bad man does not really possess self-love after all. He falls short of the noble intentions and achievements of the good man, who is a self-lover, and can have no claim at all of self-love.