This is a section from Ronnie deSousa's greaat article in the Stanford Encyclopedia Of Philosophy.

10. Morality and Emotions

The complexity of emotions and their role in mental life is reflected in the unsettled place they have held in the history of ethics. Often they have been regarded as a dangerous threat to morality and rationality; in the romantic tradition, on the contrary, passions have been placed at the center both of human individuality and of the moral life. This ambivalence is reflected in the close connections between the vocabulary of emotions and that of vices and virtues: envy, spite, jealousy, wrath, and pride are some names of emotions that also refer to common vices. Not coincidentally, some key virtues -- love, compassion, benevolence, and sympathy -- are also names of emotions. (On the other hand, prudence, fortitude and temperance consist largely in the capacity to resist the motivational power of emotions.)

The view that emotions are irrational was eloquently defended by the Epicureans and Stoics. For this reason, these Hellenistic schools pose a particularly interesting challenge for the rest of the Western tradition. The Stoics adapted and made their own the Socratic hypothesis that virtue is nothing else than knowledge, adding the idea that emotions are essentially irrational beliefs. All vice and all suffering is then irrational, and the good life requires the rooting out of all desires and attachments. (As for the third of the major Hellenistic schools, the Skeptics, their view was that it is beliefs as such that were responsible for pain. Hence they recommend the repudiation of opinions of any sort.) All three schools stressed the overarching value of "ataraxia", the absence of disturbance in the soul. Philosophy can then be viewed as therapy, the function of which is to purge emotions from the soul (Nussbaum 1994). In support of this, the Stoics advanced the plausible claim that it is psychologically impossible to keep only nice emotions and give up the nasty ones. For all attachment and all desire, however worthy their objects might seem, entail the capacity for wrenching and destructive negative emotions. Erotic love can bring with it the murderous jealousy of a Medea, and even a commitment to the idea of justice may foster a capacity for destructive anger which is nothing but "furor brevis"-- temporary insanity, in Seneca's arresting phrase. Moreover, the usual objects of our attachment are clearly unworthy of a free human being, since they diminish rather than enhance the autonomy those that endure them.
The Hellenistic philosophers' observations about nasty emotions are not wholly compelling. Surely it is possible to see at least some emotions as having a positive contribution to make to our moral lives, and indeed we have seen that the verdict of cognitive science is that a capacity for normal emotion appears to be a sine qua non for the rational and moral conduct of life. Outside of this intimate but still somewhat mysterious link between the neurological capacity for emotion and rationality, the exact significance of emotions to the moral life will again depend on one's theory of the emotions. Inasmuch as emotions are partly constituted by desires, as some cognitivist theorists maintain, they will, as David Hume contended, help to motivate decent behavior and cement social life. If emotions are perceptions, and can be more or less epistemically adequate to their objects, then emotions may have a further contribution to make to the moral life, depending on what sort of adequacy and what sort of objects are involved. Max Scheler (1954) was the first to suggest that emotions are in effect perceptions of "tertiary qualities" that supervene in the (human) world on facts about social relations, pleasure and pain, and natural psychological facts, a suggestion recently elaborated by Tappolet (2000).
An important objection to that view that has been voiced by D'Arms and Jacobson (2000a) is that emotions may have intrinsic criteria of appropriateness that diverge from, and indeed may conflict with, ethical norms. Appropriate emotions are not necessarily moral. Despite that, some emotions, specifically guilt, resentment, shame and anger, may have a special role in the establishment of a range of "response-dependent" values and norms that lie at the heart of the moral life. (Gibbard 1990, D'Arms and Jacobson 1993). If any of those variant views is right, then emotions have a crucial role to play in ethics in revealing to us something like moral facts. A consequence of this view is that art and literature, in educating our emotions, will have a substantial role in our moral development (Nussbaum 2001). On the other hand, there remains something "natural" about the emotions concerned, so that moral emotions are sometimes precisely those that resist the principles inculcated by so-called moral education. Hence the view that emotions apprehend real moral properties can explain our approval of those, like Huckleberry Finn when he ignored his "duty" to turn in Jim the slave, whose emotions drive them to act against their own "rational" conscience (Bennett 1974; McIntyre 1990).
This suggestion about the relevance of emotion to ethics must be sharply distinguished from "Emotivism"--the claim that emotions can be used to elucidate the concept of evaluation itself. Such elucidation would only be plausible if we understood the explicans more clearly than the explicandum. But the variety and complexity of emotions makes them poor candidates for the role of explicans. The view in question must also be distinguished from the sociobiological hypothesis -- which had early precursors in Mencius and Hume -- that certain motives of benevolence are part of the genetic equipment which makes ethical behavior possible. That plausible view has attracted surprisingly energetic opposition in recent years. One objection against it is one directed against all forms of ethical naturalism: namely that the biological origins of a sentiment have no obvious bearing on its ethical value. Nevertheless, sociobiological naturalism does hold out a promise of explaining both the existence of some of our more benevolent emotions and attitudes, and the way in which their scope often seems so dangerously limited to the members of some restricted in-group.
The range of emotions to which the sociobiological hypothesis can be applied, however, is relatively narrow. That many complex emotions are to a certain extent socially constructed, is attested by the fact that what is considered normal emotion varies between epochs and cultures. Feminists have pointed out, in particular, that gender-specific norms on emotional experience and expression have been a standard means of maintaining inequality among the sexes in many cultures (de Beauvoir 1952). Viewed in this light, the emotions in general lack that property of universalizability which many philosophers have regarded as a sine qua non of the ethical (Blum 1980). On the other hand, the extent and significance of cultural differences are still a matter of considerable controversy (Pinker 2002). Any conclusions about the place of emotions in the moral life must therefore remain highly tentative.