When I read philosophy as an undergraduate, both in my introductory course and in beginning symbolic logic, our professor explained why "emotivism" is not a valid means of argumentation. To say, for example, "Abortion! Ugh!" does not constitute an argument at all. Experience abounds in proving that "feeling" my way though high school multiple choice exams--especially in algebra--invariably earned me a D-minus. It is for this reason that I will often interrupt someone who. whilst opining, begin by saying "I feel that..." A number of public policies often gain traction thanks to how strongly-felt feelings are. "Facts," someone rightly observed, "don't care about your feelings."
It is for this reason that Aristotle also called the 'sensitive soul' (or the 'sensitive part' of the soul) the "irrational part" in contrast to the intellecutal soul being the "rational part." Aquinas demonstrates the irrationality of the unregulated passions by invoking St John of Damascus: "Passion is a movement of the sensitive appetite when we imagine good or evil: in other words, passion is a movement of the irrational soul, when we think of good or evil" (1a 2ae, q. 22, art. 3, sed contra). Aquinas explains further--
...passion is properly to be found where there is corporeal transmutation. This corporeal transmutation is found in the act of the sensitive appetite, and is not only spiritual, as in the sensitive apprehension, but also natural. Now there is no need for corporeal transmutation in the act of the intellectual appetite: because this appetite is not exercised by means of a corporeal organ. It is therefore evident that passion is more properly in the act of the sensitive appetite, than in that of the intellectual appetite; and this is again evident from the definitions of Damascene quoted above (respondeo).Hence Horace's Ira furor breva est or, in contemporary idiom, "Don't let your emotions cloud your judgment."
But Aquinas explains that the passions are neither good nor bad (q. 59, art. 1, sed contra); the question, rather, is whether they are directed by the reason or not: If they are, we have ordinate passions; if not, we have inordinate passions (art. 2, sed contra et respondeo). Rather than to distrust the passions (as the Stoics did), Aquinas (following Aristotle and Augustine) sees value in them as they are able to be subjected to the reason in way analogous to how the body ought to be subject to the soul. With temperance governing concupiscence and fortitude governing irascibility, these passions can then become powerful drives in one's increasing rectitude.
The reverse of this--the passions overriding the reason--is the raison d'etre of cognitive therapy practised by many licensed psychologists. I have been privileged to see up close how such a method works in people suffering from depression: The psychotherapist helps the patient to reason through certain emotions which are demonstrated to be irrational (such as the general sense of being disliked, feeling worthless, and so on). One tool that such a psychotherapist may use would be to queue up all of the patient's positive qualities to give reason that life is worth living or he or she really is liked by his or her friends.
Cognitive therapy, it seems to me, is an (inadvertent) application of how Aquinas sees reason guiding the passions. In fact, Aquinas hints at his later, fuller treatment of the virtue of prudence at 1a 2ae, q. 59, art., 1, respondeo and how it, in turn, governs all of the other cardinal virtues. The difference between 'passions' and 'virtue,' says Aquinas, is that whereas the former is a "movement of the sensitive appetite," the latter is a "habit" which is a principle of right action.
What are we to make of, then, 'religious fervour'? Ever since Ronald Knox's Enthusiasm, the Anglophone Church has tended to eschew excitement arising from piety. One often hears this criticism about the Catholic Charismatic Renewal, especially from the perennially irascible Peter Kwasniewski.
Paul Murray OP has done well in explaining the role of joy in classical Dominicanism (The New Wine of Dominican Spirituality: A Drink Called Happiness [New York: Bloomsbury, 2006]) by a close reading of St Thomas Aquinas. In fact, the expressions of religious fervour in St Dominic often stand in stark contrast with the seemingly passionless cerebralism of many of his contemporary children; Prof Dr Alan Schreck has suggested that contemporary stress on an 'unenthusiastic' religious praxis owes to Knox's influence (cf. "Enthusiasm Revisited," in Rebuild My Church [Cincinatti: Servant Books, 2010], 141-180).
The key, I would suggest, is that an excited passion uninformed by reason (such as we see in the Appalachian variety of Pentecostalism) better serves Knox's critique, rather than a reason which excites the passions which ought to be the ideal of the ferviour we see among Catholic Charismatics. But reasoning of what? In a word, the Gospel which exceeds the desires which God has placed in the human heart.
It remains to be explored how Lk 10:21, "Jesus rejoiced in the Holy Spirit" works within the framework of Christian anthropology. My initial suggestion would be that since the passions of concupiscience and irascibility are rectified by the virtues of temperance and fortutide respectively, which in turn are perfected by the gifts of Fear of the Lord and Fortitude respectively, the Septenary does has a decisive role to play. Since the gifts operate in a more unified way than do the virtues, the summit of the gifts--Wisdom--has much to do with authentic religious fervour, since it "considers the highest cause," which in tun inflames the other gifts with greater intensity, affecting also the passions. It is clear, then, that with Wisdom, the passions are subordinated to reason, which is preoccupied with some Gospel truth as this gift is wont to do.