Philosophical Rhetoric

I knew Henry Johnstone as a colleague and friend for nearly three decades, one of which was the decade (1976–87) during which I served as editor of Philosophy and Rhetoric. My editorship fell between Johnstone's first tenure as founder and editor and his second period of editorship, during his retirement. Johnstone introduced me to the importance of rhetoric while we were colleagues at Penn State. Before that time, I had the usual prejudice of philosophers against rhetoric, deriving from Descartes' exclusion of rhetoric from truth in the Discourse, Locke's designation of rhetorical statements as "perfect cheats" in the Essay, and Kant's nasty claim in the third Critique that ars oratoria "ist gar keiner Achtung würdig," that it deserves no respect whatsoever.

Johnstone was from beginning to end a logician. He made his initial reputation in philosophy as the author of a logic textbook. Because he took logic seriously, as the heart of philosophy, he was led to write Philosophy and Argument (1959). It became one of three widely read books on philosophical argumentation and reasoning published within a few years, the others being Stephen Toulmin's The Uses of Argument (1958) and John Passmore's Philosophical Reasoning (1961). These works came at a time when many professional philosophers were claiming, to each other and in their classrooms, that to philosophize is to argue, and that the validity of all arguments could be assessed by the application of symbolic logic to what was said. Johnstone, Toulmin, and Passmore showed that more was involved in the evaluation of philosophical arguments than could be gotten from formal logic.

Johnstone's Philosophy and Argument begins with the problem of disagreement in philosophical argument and claims that something more than the principles of formal validity is required for its resolution, and concludes with the sense in which argumentation is rooted in selfhood. This feature of argumentation led Johnstone to publish, just over a decade later, The Problem of the Self (1970), and a little less than a decade after that to recapitulate his own philosophical development in the collection of his essays, Validity and Rhetoric in Philosophical Argument (1978).

What is Johnstone's approach to rhetoric as connected to philosophy? To what extent is his approach complete, that is, to what extent does it require supplementation and development? Johnstone's views have been commented on by many. It is not my intention to explain his conception of rhetoric and philosophy in its complexity. My aim is to elicit the inner form of Johnstone's thought as a philosopher, to describe the problem that originates and drives his position, to see the woods instead of the trees.

Johnstone's problem was as follows: Philosophers make claims about the nature of things, the nature of knowledge, the nature of human existence, and so forth. These claims must be tested by argument. In argument, philosophers aim at validity. The principles of validity are determined in logic. Philosophy is about controversy; it is a critical activity. When there is disagreement in philosophy, formally valid arguments can be produced by both sides. How are philosophical disputes to be resolved?

In disputes occurring in fields of empirical and scientific knowledge there are open avenues for their resolution. Such fields contain methods of experimentation and investigation that allow for the production of evidence and facts that can settle such disputes. But, in philosophical reasoning, what can count as evidence or as a fact is itself in dispute. A fact is a fact only in accord with a specific theory. In philosophical controversy it is the theory that is in dispute.

The standards of empirical objectivity in scientific investigation make possible the use of argumentum ad rem to resolve a dispute. The thing to which thought can appeal is not itself in question. In philosophical dispute, as Johnstone claims, argumentum ad rem can go nowhere, because the nature of the thing appealed to is itself at the basis of the dispute. Philosophical argumenta ad rem can all be valid if properly formulated. The standard of objectivity of thought that logic can supply cannot resolve the controversy. This leads Johnstone to...