In Book Two, Chapter Three of the Nicomachean Ethics, Aristotle distinguishes three forms of the good: what is pleasurable or enjoyable (τό ἡδύ), what is useful or advantageous (τό συμφέρων), and what is right or beautiful (τό καλόν). In other places in his writings on both ethics and biology, he distinguishes three forms of reaching or desire (ὄρεξις): craving or appetite (ἐπιθυμία), feeling or passion (θυμός), and decision or will (βούλησις). Various interpreters (such as John Cooper in his book Reason and Emotion) have attempted to align these two sets of three, whereas other interpreters (such as Giles Pearson in his book Aristotle on Desire) have criticized such attempts as forced, misguided, and not supported by the textual evidence. Although I tend to agree with the integrators because I believe Aristotle was a fairly systematic thinker, I think Cooper's connection of θυμός with τό καλόν isn't right. Instead, it seems to me that craving or appetite is for the pleasant or enjoyable, feeling or passion is for the useful or advantageous, and decision or will is for what's right or beautiful.
This line of argument is opposed to both Cooper and Pearson with regard to θυμός and τό συμφέρων, so I'll sketch out my thinking here. First, let's look at the things that one might gain in life, that might be useful, that might lead to advantage. Since these are not the things that are purely pleasurable or enjoyable (especially physical objects of craving like food and drink and sex - although Aristotle says that in an extended sense there is ἐπιθυμία for higher things like learning), nor the things that are right or beautiful (such as personal excellence, knowledge, and virtue), they must be something else. The best candidates seem to be external goods such as wealth, but especially honor, societal position, respect, and reputation (as pointed out by Fortenbaugh in Aristotle on Emotion and Konstan in The Emotions of the Greeks, at least in classical times the Greeks were very much oriented toward relative status in their communities).
If we look at Aristotle's various lists of the emotions in De Anima, Nicomachean Ethics, Eudemian Ethics, and Rhetoric, we can see that most of them are, or can be construed as, fundamentally social or comparative: anger or ὀργή is triggered by being slighted or disrespected or attacked (and thus losing something you value or losing face in your community), envy or φθόνος is a desire to have what another person has, jealousy or ζῆλος is a desire that someone else not have what they have, fear or φόβος is a desire not to lose what you have (up to and including your own life), pity or ἕλεος is what you feel when someone undeserving loses what they have, regret or πόθος is what you feel when you have lost something, boldness or θάρσος is assertiveness about seeking advantage, shame or αἰδώς occurs if you lose face, delight or χαρά is what you might feel if you have gained something of great value, love or φιλία is what you feel for something or someone you want to gain (note that there are dozens of Greek words beginning with φιλο- such as φιλοθηρία for love of hunting or φιλοκυδής for love of glory), hatred or μῖσος is what you feel for something or someone that threatens you or what you have, etc. These emotions could all be varieties of θυμός or at least could arise in what Aristotle calls the θυμοειδής (the seat of or capacity for θυμός); although Aristotle never comes out and says that directly about all of these feelings, he says that about enough of them (e.g., ὀργή, φόβος, φιλία) that I think we can generalize.
For Aristotle, the conscious resolve to pursue what's right is distinctively human, whereas we share cravings for what's pleasurable and feelings for what's advantageous with other animals (ἐπιθυμία and θυμός are non-rational, whereas βούλησις is rational). Yet human beings are not disembodied minds: thus the best form of living is to integrate all three forms of the good by finding the highest pleasure and truest advantage in activities and practices for the sake of τό καλόν; the result is a seamless combination of right reason (ὀρθός λόγος) and right reaching (ὀρθός ὄρεξις). I'll have more to say about that in my forthcoming book on Aristotle.
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