Most of us who write non-fiction will at some point desire to persuade our readers of some thesis. I see this as a natural extension of the persuasive dialogue into which everyone enters during daily conversations, trying to convince another interlocutor of some view. Writers have an uninterrupted space to themselves in which to develop a case at length. Perhaps they have a particular reader in mind, real or imagined, whom they hope to convince or impress.
There is an old, old battle between rhetorical and philosophical approaches to argument. As mentioned in an earlier post, I’m currently studying Plato’s Gorgias so this battle is on my mind. Some seek to persuade by their manner of presentation, appealing to the emotions of the listener, but with little regard to the truth of the matter. They wish merely to attract supporters. Others, the philosophers, are motivated by truth alone and think the only grounds for support should be a position based on good reason and argument. That seemed to be Socrates’, undoubtedly idealised, characterisation.
Philosophers are the true experts in good argument and the real specialists are the logicians. I’m not an expert logician at all, though I did once have to teach a logic module at short notice. My own logical training was idiosyncratic since it consisted only in the outdated ancient syllogistic. I enjoyed it as a student as it was the one part of my philosophy syllabus where there were right answers and it was easy to gain perfect scores. When teaching, I had to be more contemporary since the course content dictated I teach truth tables, predicate calculus and natural deduction.
It was natural deduction where I thought the fun really started. The decision procedures for syllogisms and truth tables were algorithmic: simply follow the steps and you would come up with the right answer. Natural deductions require more creativity. There are rules, of course, but you have to decide which rules to apply, seeking the most economical and elegant proof. I loved the way that logic could be seen as an art and not merely a science. With more practice, I got a sense of what rules are best applied in what contexts but it still felt like a stab in the dark. You sometimes have to go out on a limb and see if it works out in the end.
The appeal of this more creative approach to formal logic is that it reflects our real argumentative situation when writing to persuade others, as we sit down with that blank page in front of us. We have to invent the informal arguments. Should we argue analogically, inductively, by counterexample or reductio ad absurdum? Recently, I’ve enjoyed constructing inconsistent triads, where three claims each looks persuasive but they cannot be true together so at least one of them must be false. I’m realistic enough to recognise that argumentative creativity must extend to the inclusion of some rhetoric too, though. The way in which we present our arguments can play a major role in their success. I have a suspicion, for instance, that Humeanism is so popular because Hume was very good at writing persuasively, even though his philosophy is ultimately absurd. The balance I seek to achieve between rhetoric and philosophy, therefore, is that I’m willing to use rhetorical devices but only in the service of truth and validity. I guess, though, that almost everyone thinks that this is what they do.
Stephen Mumford Blog 