In his Rhetoric Aristotle identifies the three canonical modes of artistic proof: ethos, pathos and logos on grounds that, in order to persuade, one must exude good character, move the audience by appealing to emotions, and, of course, advance good reasons. Aristotle further asserts that a trustworthy character is one of the requisites of persuading because persons are more readily persuaded by those whom they can trust.
At the beginning of Book II Aristotle subdivides ethos into phronesis, arete, and eunoia because, in order to establish credibility, the rhetor's words must project practical wisdom, virtue, and good sense. Aristotle discusses this tripartite division wholly in terms of the techne of rhetoric. Phronesis has not traditionally been associated as directly with rhetoric as the concepts of stasis and topics, but, as the above sketch underscores, its role in rhetorical reasoning is ubiquitous indeed. Understood with precision, rhetorical reasoning guides and phronesis drives moral inquiry. The aim of moral inquiry is rendering sound judgment, but judgment in hard cases is frustrated because the crux of the matter is hedged in by a potentially limitless parade of particulars. Rhetorical reason manages particulars by systematically determining the relevance of issues and identifying the stasis (which is the most relevant of the relevant issues). Now ascribing relevance, per se, is an act of phronesis.
Phronesis drives practical judgment in at least five distinct, discernible, nuanced ways: (1) by bringing to bear ethical principles where appropriate, (2) by bringing to bear past experience on present situations, (3) by generalizing from analogous cases to present ones, (4) by working in tandem with special topics to guide inquiry by determining which issues are most relevant, and (5) by combining all four aspects above to bring together probabilities in their convergence in order to facilitate praxis.