Oftentimes, a student beginning in logic believes that this study will enable him or her to win arguments, convincing interlocutor and audience alike. But even after a great deal of study and many attempts, expectations and reality remain far apart. Others, particularly in this “post-truth” world where facts seem to account for little but favorable narrative for everything, may abandon logic in pursuit of rhetorical mastery. What need is there, it is asked, for logic, if rhetoric alone affects persuasion? Does it matter why you believe, so long as what you believe is truly good?
Yes: it does matter. Let us listen to John Deely.
From Logic as a Liberal Art:
The terms “convincing or unconvincing” here need to be carefully understood. As far as logic is concerned, what is at issue is intellectual or conceptual conviction, as distinct from persuasion, which may or may not be intellectually justified on strictly logical grounds. Rhetoric, which is also concerned with convincing people, studies persuasion in the broadest sense, as including, but not restricted to, logical persuasion. From the point of view of rhetoric, logic is one of the tools, but by no means the only one. Indeed, one of the ways through which, historically, rhetoric acquired something of a bad name was from treating logic not as an instrument, but as an obstacle to be gotten around in the interests of carrying the day independently of the intellectual merits of the position being advocated. Thus the convincingness of a discourse in its totality goes well beyond logic to mark out a much larger domain, that of rhetoric in the basic sense. We find something convincing often for reasons that have little to do with reason in any strictly logical sense, and, conversely, we find some statements put together in the most logical manner utterly unreasonable and wholly unconvincing. Ideally, we would agree that the truth of any given case deserves the clearest and most convincing formulation possible. But this is not something that “just happens” (i.e., a clear and convincing formulation is not a speculative truth in Aristotle’s sense), it is something that is up to us to make happen, to the extent it happens at all. Clarity of formulation is a matter of “practical truth”.
Coherence, consistency, and convincingness, then, are not all on a par in defining the subject matter of logic. They are part of a pattern, but the aspects of the pattern which make it coherent and consistent are what logic studies first of all, in order to ensure that “what we find convincing” about a given discourse is as rational as possible. The subject matter of logic—that which we study or investigate when we inquire into logic—is some kind of pattern immanent or “living within” our discourse, whereby that discourse has in any given case the properties of coherence and consistency especially, but other properties as well, as we shall see, on which coherence and consistency depend. Just what this pattern is can be seen from one of the simplest and, at the same time, most accurate statements of what logic is, a statement made by Charles Sanders Peirce in 1883 (2.710): “The very first conception from which logic springs is that one proposition follows from another.”
Logic studies the way one proposition follows from another: it is the study or doctrine of consequences in the broadest sense, but especially, as we shall see, those consequences which obtain among propositions in the context of argument. We may indeed take this as a first definition of logic, though it will take much of the following book to set out in something like an adequate way what the formula means. Logic is concerned with that part of “being convinced” which can be reduced to intellectual reasons clearly stated in relation to conclusions they support, in order to show that the conclusions in question truly follow from the reasons alleged. Thus logic in general can be defined as the doctrine of valid consequences drawn in the sphere of rational discourse. Logic is a part of rhetoric, to be sure, but that part leaves out of account as far as possible the emotional, psychological, sociological, political, and commercial factors, in order to concentrate on persuasion precisely inasmuch as it is or can be rooted in the purely intellectual consequences (the unavoidable consequences for understanding, let us say) of rational connections symbolically formed. Logic, thus, is concerned with the intelligible structuring of the way things are thought to be.
John Deely i.1985-2015: Logic as a Liberal Art, 3-4.
Consequences of Illogical Rhetoric
We may affect coherence, consistency, and convincingness in our rhetoric, that is, without logic: but we do so without the reasons why. To convince… without reason? Is this rightly human? Katherine Maher, the newly-appointed CEO of NPR, was recently much lambasted for her depiction of truth in a 2022 TED Talk. While many have needled the apparent relativism of her comments, I would highlight instead the elevation of the pragmatic over the true. In Maher’s own words, with my emphasis, “In fact, our reverence for the truth might be a distraction that is getting in the way of finding common ground and getting things done.”
And this “getting things done” is precisely what one may affect through a rhetoric absent logic. Your efforts may even produce truly good results. Attention to the truth and the why of their accomplishment—attention which requires logic—may slow down the production of such results.
Of course, without logic or tending to the truth it will not be known why such results are good.
Indeed: any coherence or consistency we produce through logic-devoid rhetoric will be the product of either chance or experience, but not of knowledge. As Deely puts this, “the aspects of the pattern which make it coherent and consistent are what logic studies first of all”. We are unlikely to maintain coherence and consistency for very long, that is, without such a study. Certainly, we may do so in a single argument. But over the years, decades, centuries? How are our thoughts to persist in convincingness if we cannot even articulate how one follows the next?