ISSA Proceedings 2002 – The Relationships Among Logic, Dialectic And Rhetoric

logo  2002-11. Introduction
A consideration of the relationship among logic, dialectic and rhetoric was found already in the work of Plato and Aristotle and others in the first golden age of Western philosophy, and this relationship has received attention down through Western history (see the historical observations in Krabbe 2000, Hohmann 2000, and Leff 2000). The late 20th century argumentation scholarly community was reminded of its salience (see Wenzel, 1980) and has returned to its examination. In the last five years or so, a flurry of activity has raised the profile of these questions in this community, particularly with the focus on how dialectic and rhetoric and their relationships bear on the identification, interpretation and assessment of arguments and argumentation (see the special issues of Argumentation edited by Hansen and Tindale 1998, and by van Eemeren and Houtlosser 2000a).

In the English-speaking philosophical community, in contrast, there has been little attention to argumentation at all, to say nothing of the relations among logic, dialectic and rhetoric. (The work of Henry W. Johnstone, Jr. is a noteworthy exception.) However, in the last thirty years a small number of philosophers, some of whom characterize their field (for rhetorical reasons) as “informal logic,” have been working out the implications of expanding the analysis and assessment of arguments beyond the identification of the deductive or entailment relationships they might exhibit. In broadening the scope of their perspective in this way, they initially (and belatedly) recognized the bearing of dialectic (see, for instance, Blair and Johnson, 1987), and more recently, the importance of rhetoric (see, for instance, Tindale, 1999). In doing so, they raise for themselves the question of the relationship among the three.

So, under the influence of the recent attention to rhetoric and to the relation between dialectic and rhetoric by the broader community of argumentation, and also due to their own internal theoretical development, some philosophers working in informal logic have come to an interest in these issues. It is from this historical situation that my own interest in this topic arises. This paper is an attempt to come to grips with the relationship of these three fields or perspectives. To begin, I explain the senses of logic, dialectic and rhetoric used in the paper. If the paper has a thesis, part of it is that there is no one type of relationship among these three, but rather several – at least four, and there may be more. For each of these types of ways the three can be related, the question arises as to how they in fact are related. The other part of the paper’s thesis is that even for each type there is not always only one way the three are related.

2. The concepts of logic, dialectic and rhetoric used in this paper
According to the Amsterdam school, argumentation is, or is most perspicuously to be interpreted as if it were, a particular kind of speech event (van Eemeren and Grootendorst 1984, 1992). As I understand it, according to the Pragma-Dialectical theory, argumentation presupposes an expressed disagreement. The word ‘disagreement’ is here used in a technical way, to denote a lack of complete identity of commitment. For example, if Anna states confidently that a certain restaurant will be open, and Ben, knowing that Anna sometimes has misplaced confidence in such things but no particular reason to doubt that she is right in this case, responds, “I hope so,” then Anna and Ben have a disagreement in the sense in question. So at a minimum, argumentation presupposes an expressed disinclination of at least one party to commit to precisely the same position or “standpoint” that another party expressedly does commit to, regardless of how similar their positions are otherwise. They disagree at least on some specifiable particular point. If the parties decide to try to settle their disagreement by engaging in a discussion, and the ensuing exchange is properly regulated, that is, regulated by the norms necessary and sufficient to procure a rational resolution of the disagreement, then (among other things) each party defends its position using logically-acceptable arguments. Such arguments are thus components of the overall communicative interaction of argumentation.

It is possible to consider arguments apart from their use in argumentation so conceived. Even each party in a Pragma-Dialectical “critical discussion” must consider both which arguments to offer or express and also which arguments on offer or expressed by other parties to accept. To be sure, the context of argumentation is essential to the interpretation of the arguments, but once they are interpreted in light of that context, one must consider their “logic.” By considering their logic, I mean that if it is an argument on offer, one can ask, “Do the grounds offered make it rational for me to accept the position they allegedly support?” If it is an argument one is considering offering and one is committed to a rational resolution of the disagreement, one can ask, “Do the grounds make it rational for me and my interlocutor to accept the position in support of which I am considering offering them?” To my knowledge no one has established that arguments cannot, ideally, be used for other purposes besides the rational resolution of disagreement. If it turns out that arguments can be put to other uses, then the question of their “logic” can be raised in those other contexts as well.

If one wants to reserve the word ‘argument’ to denote reasons that someone is publicly committed to, then we would need another word for the organized thoughts entertained by an interlocutor independently of whether he or she makes them public. We might then speak of the interlocutor’s reasoning, and so of the logic of his or her reasoning. And we do speak this way. However, no one owns the word ‘argument,’ and there is a long and respectable history in philosophy, and in non-technical English as well, of referring to such potential contributions to argumentative discourse as “arguments” and “reasoning” more or less interchangeably, whether or not they end up as someone’s public commitments.

My use of the word ‘logic’ might seem idiosyncratic to scholars who identify themselves as logicians. For example, Woods has said that “no theory is a logic if it lacks proof procedures” (1995, 192). To my knowledge there are no proof procedures available to answer the question that I’ve just suggested it is a task of logic to answer, namely, whether the grounds on offer make it rational to accept the position they are adduced to support. I stand to be corrected by logicians, but taking Woods as authoritative, the term ‘logic,’ “strictly speaking,” would denote the study of, and systems of, proof procedures for the necessary or entailment relations among sets of sentences, for different kinds of operator. Understanding ‘logic’ in this way, one can speak of examining the “logic” of someone’s argument or reasoning when one means examining it to see whether the premise sets used entail the conclusions derived from them according to some logical system. But as is well-known, logical validity in this sense is neither a necessary nor a sufficient condition of a rational or reasonable argument. My use of ‘logic’ – Woods might say, my corrupt use of ‘logic’ – has the virtue of allowing for the possibility that reasoning or an argument might be logical in the sense that it is rational to use it or to accept it, even if its premises do not entail its conclusion. For instance, it might be invalid yet inductively strong, or it might be invalid but highly plausible. Or it might be invalid as it stands, but open to reconstruction that makes it valid if and only if some additional premise is accepted. In the latter case it becomes necessary, in order to decide whether the enriched premise set that entails the conclusion should be taken to be the argument, to decide whether it is reasonable to believe or accept that additional premise, which is not a logical question in the strict sense of ‘logic.’

Some (e.g., Goldman 1985, Pinto 1994) have said that, understood in the broad sense, logic is not an independent field, but a branch of epistemology. Johnson (2000, 281-283) has listed a number of reasons for resisting the reduction of  logic in the broad sense to epistemology, but even if he is wrong, that implication is no reductio objection against using ‘logic’ in this broad way, because the arguments for the subsumption of such logic under epistemology rely precisely on distinguishing it from logic in the strict sense. Anyone who wants to reserve the word ‘logic’ for logic in the strict sense might allow the term ‘informal logic’ to designate what I am calling logic in the broad sense.

However, let us resist terminological imperialism. One need not favour terminological anarchy to hold that if there is a healthy tradition of the use of a word in a certain way, that gives it some claim to legitimacy, even if it lacks the theoretical purity of a technical sense assigned to it by some science. Nobody owns the language, and just as the Pragma-Dialectical school does not own the word ‘argument,’ so too professional logicians do not own the word ‘logic.’ They are of course free to assign to it a precise technical sense for their purposes, but if others use it in other ways, logicians have no business telling them that on that ground alone they are misusing the word. What logicians can do is point out that this other use is different from theirs, and it can be important to keep that fact in mind. However, to declare that the term ‘informal logic’ is a solecism, as Hintikka has done as one criticism of informal logic (1989, 13), is irrelevant to the question of the legitimacy of the enterprise that is carried on under that name. Hintikka’s reasoning is like saying that the name ‘football’ is a solecism for a game that requires the player to carry the ball in his hands, and from that observation drawing the inference that there is something wrong with American or Canadian football. But that point aside, there is a perfectly good use of ‘logic’ according to which an argument’s logic can be deemed acceptable although the premises do not entail the conclusion and can be deemed faulty although they do entail the conclusion.

In evaluating the reasoning or the arguments in argumentation for various purposes, we are interested in their logical strength. To be sure, their logic can enter into the prior identification and interpretation of arguments, because one indication that a piece of discourse is an argument is that it contains a logically cogent case for a claim. In addition, even where situational and textual indicators suggest independently that an argument is present, what argument the discourse is taken to contain can be a function of what reconstruction of it is logically cogent as support for a claim. However, the principal reason we want to identify and interpret argumentative discourse is because we are interested in evaluating the logical merits of the reasoning or arguments expressed in it, for some purpose or another. One primary reason for this interest is that we want to decide whether we ourselves should be convinced by that reasoning or by those arguments.

However, if we focus particularly on arguments used in argumentation, there is another dimension to be taken into account besides their logic, when considering their adequacy for various purposes. Argumentation constitutes an activity in which there is a question about whether, or at least why, a position is worthy of belief or acceptance. And typically there is more than a question. More often, doubt about a point of view or disagreement with it is either voiced or anticipated. The practice of argumentation presupposes the questioning of a point of view. Objections to a protagonist’s arguments, and arguments against the position a protagonist is supporting, have to be met by the protagonist. He or she has either to produce additional arguments or to explain why it is not necessary to do so. If dialectic is understood broadly as question-and-answer interchanges, then the practice of argumentation is inherently dialectical.

Why do objections “have to” be met? Why does the protagonist “have to” produce a reply, or explain why not? Why “must” argumentation be dialectical? What is the basis of this imperative?  First, there is the practical matter of convincing the interlocutor. If his or her objections are not answered, the argumentation will fail in its objective. So there can be and usually is a rhetorical basis for meeting dialectical challenges. Second, and quite apart from winning the argument or succeeding in persuading the interlocutor, if the protagonist argues for the position because he or she believes it to be true (or highly probable, or very plausible, or the best alternative, or worthy of acceptance on some other basis), then, in order to be fully justified in that belief, he or she must be able to answer not only this or that particular interlocutor’s objections, but any other reasonable objections that he or she can discover. To be sure, we allow for qualified assertions when the protagonist has made only a partial inquiry, and the extent of the search for possible objections required for full confidence in an assertion is a matter of debate (see the discussion of Johnson’s concept of a “dialectical tier”: Johnson 1996, Govier 1997, 1998, Johnson 2000a); but being able to deal with objections in general is a condition of reasonable belief. So there is an epistemic basis for meeting dialectical challenges as well (see Goldman, 2000).

The epistemic basis for requiring dialectical rejoinders in argumentation has a rationale that is related to the protagonist’s objective of rationally justified beliefs. The very practice of argumentation – of advancing arguments with the expectation of their making a difference to the beliefs, non-cognitive attitudes or conduct of others and of expecting others to supply arguments in support of positions they propose – would have no point without the background assumption that having, or giving, reasons is having or giving more than a rationalization. The practice of argumentation presupposes that having or giving arguments is rational in some sense (see also Biro and Siegel 1991, Johnson 2000b). At the least, it imposes a requirement of consistency with our current beliefs and attitudes. And if there are any foundational starting points for conduct or attitudes (including epistemic attitudes), argumentation is the means of tying our current beliefs and attitudes down to those foundations.

There seem to be various kinds of norms that characterize dialectical interchanges. Some might be called “house-keeping” rules, for they are rules that maintain a tidy exchange. “Wait for your turn” and “keep to one point at a time” are examples. Other rules are more centrally connected to the practice, and might be seen as defining it – that is, they are constitutive rules. “Meet the burden of proof” would be an example of a rule constitutive of argumentation’s dialectical aspect. What the burden of proof requirements are will vary according to the type of dialectical practice. For instance, the Pragma-Dialectical burden of proof rule is that he or she who asserts must defend if, but only if, challenged (van Eemeren and Grootendorst 1984, 161), whereas Johnson recommends that the he or she who asserts must defend unless exempted from doing so (2000b, 310). These different burden of proof rules entail, if not entirely different conceptions of argumentation, at least different purposes for it.

Some of the norms governing dialectical interchanges will be a function of the objectives of such interchanges. If you and I are arguing over some proposal we disagree about, for example, whether Able or Baker is the candidate to whom a position should be offered, and each of us has the objective of convincing the other, we will each have to answer the questions and respond to the challenges raised by the other, but no others, for once one of us has convinced the other, the objective has been met. If, on the other hand, you are trying to come to a reasoned opinion on some issue, for example, about whether the ban on killing whales should continue, you should not stop considering objections once you have looked at the arguments of actual interlocutors. Let us say that only the Japanese and the Norwegian governments have advanced arguments against the whaling ban. Your interest does not lie in refuting the Japanese and Norwegian position, but in deciding what position seems right, all things considered. Thus, besides considering the merits of the Japanese and Norwegian arguments against continuing the ban, you need to consider that there might other arguments, either against or in favour of the ban, that deserve consideration.

The differences between arguments in conversations, in the simplest case organized by the turns of a two-party dialogue, and arguments in speeches, in which the requirements of addressing a heterogeneous audience and the expectations of different kinds of speech-making occasion make quite different demands on the speaker, were noted already by Aristotle, as Krabbe has reminded us (2000). Krabbe suggested that Aristotle took dialectic to be the practice and theory of conversations and rhetoric to be the practice and theory of speeches, recognizing that speeches can contain elements of conversations and conversations can contain elements of speeches. Dialectic gives us the rules for winning dialogue games; rhetoric gives us their counterpart for successful speeches.

One hesitates to differ with Aristotle, however, I am inclined to cut the pie differently. One can identify what might be called the pragmatic properties of argumentation in both conversations and speeches. There are the different possible purposes or goals of the argumentative discourse, often several at once, and there are all the properties of the various kinds of situation in which the argumentative discourse can occur, often with their associated conventions, that necessarily condition it, whoever may be the parties involved in the discourse. My suggestion is that we take rhetoric as a discipline to include the study of the norms for most effectively achieving those purposes in those situations, whether the discourse situation be a two-party conversation (such as between parent and child, between lovers, between colleagues, between dialogue-game players); or whether it be presentation to a small group (such as an academic talk, a summation before a jury, a contribution to a policy-making meeting); or whether it be an address to a large group (such as a political speech to hundreds of party faithful, or a sermon, or a commencement address); or whether it be a presentation to an absent audience, more or less specifiable (such as a journal article or a monograph or a magazine article or a televised address); and so on. We can then speak of the rhetorical (as well as the dialectical and logical) properties both of conversations and of speeches, and indeed of any kind of communication whatever, and we do not have to try to assimilate all sorts of different kinds of communication to one or the other branch of the conversation/speech dichotomy, or model them all as either conversations or speeches.

Whether rhetoric is to be restricted to providing the norms of just effective argumentative communication, or alternatively is to be considered to provide the norms of effective communication general, are questions I do not need to try to answer, for my interest lies in rhetoric as it applies to arguments and argumentation, whether that is the whole of rhetoric or only a part of it. (The former is Reboul’s position, see 1991; the latter the view of many American scholars of rhetoric, for example Foss, Foss and Trapp, see 1991, Introduction.)

The norms of rhetoric differ in kind from those of logic and dialectic. One expects the norms of rhetoric to vary with the practices of different cultures, so that communicative behaviour that might be tolerated or expected in one could be found offensive or surprising in another, even if the communication is of the same type. A philosophy lecture that fails to trace its topic back at least to Aristotle would not on that account be condemned in most circles in the United States, but it would be in some circles in France. What makes for effective communication in general, and for effective argumentative communication in particular, is something to be discovered by empirical research. Rhetorical norms are contingent. The norms of logic and dialectic, in contrast, are culturally invariant. The kind of support expected might vary with the subject-matter, being different in mathematics, chemistry, sociology, law, public policy deliberations, and so on. And there might be different dialectical norms for different forums, being different for academic discussions, for criminal trials, for parliamentary debates, and so on. But these differences are due to variations in methodology or to functional variations in these argumentative practices, not to cultural contingencies. And what constitutes entailment, or what makes for a good longitudinal epidemiological study, does not vary from one social situation to another. It is possible that there are universal psychological traits that result in certain kinds of rhetorical norms being culturally invariant, but it remains the case that such norms are contingent, unlike those of logic and dialectic, which are necessary relative to the systems in which they operate.

3. Types of relationships among logic, dialectic and rhetoric
Understanding logic, dialectic and rhetoric in relation to argument in these ways, the question arises as to how they might be related one to another. In what follows I distinguish four different types of possible relationship. The first is the conceptual or logical relationship among the norms of the three perspectives. The second is the contingent or empirical relationship among their norms. The third I call the relationship of normative priority, and the fourth, that of priority of theoretical emphasis.

The conceptual or logical relation among logical, dialectical and rhetorical norms. Cohen (2001) has recently suggested that so far as the evaluation of arguments goes, the norms of logic, dialectic and rhetoric are logically (that is, conceptually) independent of one another[i]. According to Cohen, any argument may be assessed according to its logical cogency, its dialectical satisfactoriness and its rhetorical effectiveness. In addition, he suggests, an argument’s assessment according to one of these criteria will be independent of its assessment according to either of the others. Cohen’s view is thus a position on one type of relationship among the three perspectives, namely the logical relationship among the norms appropriate to each of them. It is a position on the question of the implications of an assessment of an argument according to the criteria of one of them for the assessment of the argument according to the criteria of either of the others. Cohen’s position on the question of this logical relationship is clear: “Arguers and their arguments,” he says, “can succeed or fail in three separate ways” (75). Thus, if he is right, where an argument fits according to the criteria of any one perspective will be logically independent of where it fits according to either of the others. In other words, there is no logical relationship – there are no implications – among evaluations from the logical, rhetorical and dialectical perspectives.

What might such a logical relationship look like, were it to exist? One has been urged by Johnson (2000b), whom I interpret to take the position that an argument is not logically adequate if it is dialectically incomplete. Johnson does not put his point quite this way. He says that an argument is logically adequate only if sufficient support is provided for its conclusion. But he also holds that sufficiency is a criterion of logic, and that support for a conclusion is not sufficient if there are objections to or other criticisms of the argument as stated so far that have not been dealt with (see Johnson, 2000b, Ch. 7). So in my way of talking, for Johnson, dialectical adequacy, at least in a certain respect, is necessary for logical adequacy. I take it that Johnson would therefore disagree with Cohen’s position.

I must add the qualification, “at least in a certain respect,” because there is more to dialectical adequacy than meeting the burden of proof. For instance, among other things it also requires providing explications and explanations when these are requested and it forbids argumentative moves that improperly limit the argumentative moves of the other parties. So, on Johnson’s account, dialectic is presupposed by logic in the respect that a necessary condition of an argument’s being logically adequate is that it be at least partly dialectically adequate. This implication seems to me right. A claim that is in question is hardly adequately supported by the grounds adduced in its support if those grounds do not include adequate responses to legitimate objections, whether to the claim itself or to the arguments put forward so far.

However, is the converse not also true? One would have thought that for a response to an objection to be dialectically adequate, it must be logically adequate. The Pragma-Dialectical theory, for example, requires as a rule of dialectical adequacy that the argumentation adduced in support of a standpoint be valid and correctly use an appropriate argumentation scheme (van Eemeren and Grootendorst 1992). That amounts to the view that logic is presupposed by dialectic in the respect that a necessary condition of an argument’s being dialectically adequate is that it be logically adequate. This implication also seems to me right. It is difficult to imagine acceptable rules of dialectic that allow logically bad arguments to count as dialectically satisfactory responses. The norms of dialectic and those of logic thus seem to be interdependent.

If this reasoning is correct and the satisfaction of the norms of logic require the satisfaction of some of the norms of dialectic, and conversely, the two perspectives are nonetheless different, because there is more to logic than dialectic and more to dialectic than logic. Dialectic has to do with rules for well-ordered exchanges of arguments, whereas logic applies only to the arguments themselves; logic has to do with rules for well-designed arguments, which includes more than satisfactory dialectical design.

Johnson focuses on logic and Pragma-Dialectics focuses on dialectic. We should also consider whether there are norms of rhetoric that have implications for those of the other two perspectives when it comes to the assessment of arguments. Rhetoric calls upon us to shape our discourse to the success of our goals, taking into account the particularities of the situation. Since it is normally a principal objective of argumentation to convince whomever it is we are addressing of the truth or acceptability of our standpoint, it follows that argumentation should be assessed from the rhetorical perspective according to how well the means used might have been expected to contribute to that objective. It seems probable that argumentation that fails to allay the objections to our standpoint in the minds of our interlocutors will not be successful in convincing them, so it looks as thought there is a rhetorical reason for being dialectically astute. However, one can imagine argumentation that manages to preoccupy the interlocutors with some particular issue, and thereby distract them from the objections that they might otherwise raise. Think if Marc Antony’s speech over Caesar’s body in Shakespeare’s Julius Caesar, that manages to preoccupy the crowd with Caesar’s generosity and thereby cause them to forget for the moment his imperial ambitions. This kind of example suggests that rhetorical effectiveness does not logically imply dialectical completeness. The converse seems true as well. It seems possible that a dialectically thorough argument could be so complicated as to become tedious, so that the audience loses track of its meanderings, loses interest, and begins to wonder whether the arguer “doth protest too much,” and as a consequence, fail to be convinced by what is in fact a dialectically satisfactory case.  So it seems that there is no necessary connection between rhetorical effectiveness and dialectical completeness.

The same kind of point applies to the connection between rhetorical and logical norms. While on most occasions it is probably more effective in convincing the interlocutor to use logically strong arguments instead of logically problematic or weak ones, it is possible to imagine cases in which logically flawed arguments are persuasive. Certainly the concern about logical fallacies (as distinct from dialectical fallacies) presupposes this possibility. And conversely, a logically tight argument might, as a result of its complexity, fail to persuade an audience that thinks the arguer is getting a bit too fancy, suspects him or her of dressing up a weak case, and consequently fails to be convinced by what is in fact a logically strong case. It would follow, then, that as with dialectical norms, any connection between the logical strength and the rhetorical success of arguments is contingent.

In sum, first, one kind of relationship among logic, dialectic and rhetoric is the logical relationship among the applications of their respective norms or criteria for good argument. Second, any argument satisfying the criteria for logical goodness must partially satisfy criteria for dialectical goodness, and conversely, any argument satisfying the criteria for dialectical goodness must satisfy those for logical goodness. Third, there is no necessary or logical relations in either direction between satisfying the norms of logic or the norms of dialectic and satisfying rhetorical norms for arguments.

The contingent or empirical relations among logic, dialectic and rhetoric. To be distinguished from the logical relationship just discussed is the empirical relationship among the three sets of norms as applied to arguments. We have seen that certain connections seem necessary, but apart from those, will there be causal connections, or at least covariance, between the satisfaction of criteria that are contingently related? Specifically, will there be positive correlations between the logical or the dialectical adequacy of argumentation (or both) and their persuasiveness? And if so, is there a causal connection or is some other factor causing both?  Or are there more complex empirical relationships. For example, one might hypothesize that, keeping other aspects of logical quality constant, as an argument takes up and deals with the objections that are dear and pressing to the audience, it will be increasingly persuasive for them, but if the argumentation continues to entertain and respond to objections that do not interest the audience, its persuasiveness for them will progressively decline. The formulation of such hypotheses, and the design and implementation of their testing, lie outside the scope of this paper.

Normative priority. Suppose that the story told above about logical relations among the norms of these three perspectives is correct. And grant that the actual effect of meeting these norms upon the audience or the argument interlocutors is a matter to be discovered by empirical investigation. What ought to happen if the norms of these different perspectives were to render conflicting advice? What if logically sound arguments were in some situations less persuasive than logical fallacious ones? What if dialectically thorough arguments were in some situations less persuasive than ones that ignored many challenges? Would it ever be appropriate to use the fallacious or dialectically incomplete arguments because of their persuasiveness? And what ought to happen if the norms of one or more of these different perspectives were violated? What if a body of argumentation were logically and dialectically impeccable, but far more difficult to understand than necessary, and expressed in ways that antagonized its audience – in short, rhetorically clumsy; should it be rejected on that account? It seems to me that here there is no one right answer, but instead it will be appropriate for the emphasis to be different in different contexts or situations of argumentation. More specifically, the purpose of the evaluation and the perspective of the agent can be determining factors. Let me give some examples.

In criminal trials, the legal system sets the objectives of the argumentation used within it, and imposes numerous constraints. The Crown or prosecuting counsel in criminal courts in the common-law system has the task of establishing the accused’s guilt beyond a reasonable doubt. The criminal defence counsel has the role of defending his or her client against the criminal charge. That requires trying to show that the Crown has not proved guilt beyond a reasonable doubt, and in jury trails (since unanimity is required) it in turn consists in trying to persuade some members of a jury that the Crown has failed to make its case beyond a reasonable doubt. Suppose we want to assess the argument of a defence counsel’s final address to the jury. How do the normative criteria of logic, dialectic and rhetoric apply? It is an obligation of the accused’s lawyer to argue for the weakness of the Crown’s case in the most persuasive manner possible. Therefore, we ought not to not condemn the defence counsel’s argument if its logic is flawed in ways unlikely to impair or, indeed, likely to help, the persuasiveness of his presentation. Nor ought we to condemn the argument if the defence counsel fails to deal with parts of the Crown’s case, if this failure is, again, unlikely to impair or likely to help the persuasiveness of his presentation. In addition, the defence counsel would be in violation of his duty to provide the best defence possible if he were to bring forward reasons for thinking his client guilty, or to raise objections that would undermine his defence. It is the Crown’s role to do those things. It is true that the adversarial system forces the defence counsel to try to deal with the evidence of the Crown, and that by failing to respond to the Crown’s arguments or evidence the defence takes the risk that the Crown will use that failure in arguing for the guilt of the accused; but these are contingent exigencies, and with sufficient imagination it is possible to concoct, and probably with enough research, to discover, cases in which the successful argument fails to meet the highest standards of logic and dialectic. Such a case would not satisfy the Pragma-Dialectical rules for a critical discussion (see 1984), nor would it satisfy Johnson’s requirement of manifest rationality (see 2000), but it might be right case for the defence counsel to make.

A successful and respected civil litigation lawyer in Canada once said that there is only one argumentation rule for litigation, namely: “Know your judge.”[ii] Part of his point was that to win a favourable ruling or settlement, it is not necessary to prove that you have the better case, but only to persuade the presiding judge that you have the better case. The other part of his point was that different judges are swayed in different ways. In principle, the logical and dialectical acumen of judges can vary. Thus, again, in such situations rhetorical virtue or persuasiveness can in principle, and should, trump logical cogency or Johnson’s requirement of dialectical satisfactoriness.

It might be objected that I am just describing certain argumentation practices, and providing no principles that would justify the priority of meeting rhetorical standards over those of logic and dialectic[iii[. That point is well taken. So let me add that these particular practices have a very long history of functioning fairly well in realizing their objectives in the criminal and civil legal systems in a number of countries. Included in those objectives are the instantiation of moral and political values. So I suggest that a case can be made that such practices are justified, and consequently that the subordination in them of logical and dialectical norms to rhetorical standards is in turn justified.

Consider a different example, a setting for argument familiar to an academic audience: the academic journal article. Since there are many sub-genres, let me focus on those in philosophy journals in the analytic tradition. In an paper submitted for publication in such a journal, a mistake in logic, if noticed, is a serious obstacle to its prospects, causing at the least a revision to, or else, unless it is just a slip that is easy to fix, outright rejection of, the paper. The demands of dialectic are almost as stringent. The author must respond, not only to the questions and objections raised by the referees, but also to those already published in the literature, and, indeed, to any others that might reasonably have been raised by anyone. An author is not even castigated for inventing an objection only to rebut it, provided that it is not frivolous. It is true that editors and referees might agree that an objection does not deserve attention when in fact it does, so there is room for a small measure of dialectical leniency. Rhetorical shortcomings, however, are tolerated, especially if the logical and dialectical merits are strong. Moreover, rhetorical virtue is supposed never to trump the requirements of logical cogency and dialectical satisfactoriness. It is a virtue of such a paper that it is clear and easy to understand and to follow, but not a requirement. (Notice that in this sort of context it is difficult to separate dialectic from logic, for a paper that fails to respond to telling objections is not logically cogent, and one that responds to objections, but with logically flawed arguments, is not dialectically satisfactory.)

Once again, the objection that I merely report norms in practice without justifying them may be made, but I would reply along the same lines as above. The practice in which these norms are imbedded functions moderately well, and, in spite of certain failings, it is difficult to imagine an alternative that would be as good. I take it that the purpose of the practice is to expand our knowledge and understanding in philosophy, and that insisting on logical rigour and dialectical thoroughness above all are necessary to that end, whereas requiring rhetorical virtue is not.

I do not know if there are general principles on the basis of which it can be determined in which situation which norms should take precedence. I have just discussed examples in which the purpose or goal of the argumentation seems appropriately to make a difference as to which perspective gets normative priority. It seems to me that the perspective of the agent can also be relevant. For instance, we take it that the person formulating and presenting the argument should ideally have the rhetorical perspective among his or her considerations – for some purposes more than for others, but always to some extent. When selecting, no less than when composing, the arguments and the organizing of their presentation, he or she should consider who the audience is, what the occasion is and what the purposes of the presentation are. However, from the perspective of the person assessing the argument with a view to deciding whether to adopt its conclusion on the basis of the reasons offered in support of it, the key perspectives seem to be logical and dialectical. Do the grounds actually lend support to the claim, and are the objections answered that need to be answered?  These are the questions the consumers of the argumentation ought to have front and centre in their analyses. To be sure, in some roles (think of being a jury member), awareness of rhetorical devices designed to sway the consumer’s opinion might be needed in order to give appropriate attention to the logical and dialectical adequacy of the case presented.  Nonetheless, the norms used to decide what to believe (for instance, whether to convict or to acquit) should not be those of rhetoric, but those of logic and dialectic. On the other hand, someone assessing the argument with a view to giving advice to the arguer as to how to be more persuasive will appropriately focus on its rhetorical merits, though not necessarily at the expense of its logical and dialectical adequacy. I conclude from considerations such as these that there is no single, universally applicable order of normative priority when considering the norms of logic, dialectic and rhetoric.

Priority of theoretical emphasis. Students of argumentation will be aware that different theories tend to give different emphasis to logic, dialectic and rhetoric. For instance, the Amsterdam Pragma-Dialectical theory consists of an ideal model for a kind of dialectical interaction within which framework logic and rhetoric have subordinate roles (see van Eemeren and Grootendorst, 1984, 1992). To be sure, for an argumentative discussion to be rational, according to this model, the particular arguments used in the process of a dialectical exchange must be logically acceptable, and within that and various dialectical constraints, the interlocutors are free to use whatever rhetorical strategies they think will help them to have the disagreement settled in their favour (see van Eemeren and Houtlosser 2000b, 2000c). But when interpreting argumentative discourse, according to the pragma-dialectical theory, we should treat it as if it were an attempt to follow the rules of the idealized dialectical model. In this respect, dialectic has theoretical priority for this theory. Perelman and Olbrechts-Tyteca (1958) or Tindale (1999), in contrast, take the position that rhetoric has, or should be deemed to have, priority over logic and dialectic. La Nouvelle Rhetorique defines logic as the science of demonstration, where rational disagreement is impossible, and conceives argumentation to occupy disagreement space where only rhetoric has application. The role of dialectic is not addressed. Tindale’s position seems to be that, because arguments are in fact always situated in particular contexts, with such variables as their specific purpose, their audience, and the circumstances of their delivery, among other things, all influencing how we should interpret them, or design them, it follows that logical and dialectical norms cannot be brought to bear before rhetorical judgements are made. On this view, the first task of argument interpretation and assessment, and of argument design and presentation as well, is to situate the argument or argumentation rhetorically, and in this respect, rhetoric has theoretical priority. Toulmin’s influential model seems intended for the logical assessment of arguments and does not include any reference to dialectical or rhetorical elaborations. And many of the philosophers identified with the informal logic movement have taken their objective to be the interpretation and evaluation of arguments, yet with only a few exceptions they do not discuss the dialectical or the rhetorical dimensions of argumentation. For the Amsterdam school, the most important feature of argumentation is its dialectical dimension; for the New Rhetoric and Tindale, the most important feature of argumentation is its rhetorical dimension; for many informal logicians, the most important feature of argumentation is its logical dimension.

Those who give priority of theoretical emphasis to just one of the three perspectives cannot all be right, but they can all be wrong. Is there some way to decide which theoretical perspective ought to be given priority?

Historically, and in different disciplines, some have been given pride of place and the others ignored, denigrated, or relegated to minor roles. Yet the philosopher who treats logic as central and primary forgets that when he or she writes a paper or makes a presentation, there is unavoidably dialectical interaction with alternative views and contending arguments, and also all sorts of rhetorical decisions have to be made in framing, organizing and presenting the case. When the cultural critic makes the rhetorical perspective central, presumably he or she argues the case, and in doing so interacts with contending views and relies on logical standards. When the communication theorist emphasizes the dialectical and pragmatic properties of argumentation, he or she nonetheless allows that to the extent that the practice is rational in some sense, norms of logic are guiding, and to the extent that it is effective, norms of rhetoric are followed. It seems that any complete theory of argumentation will account for the role of each, not emphasizing any one at the expense of the others.

However, it is understandable that different interests will result in different emphases. If the theorist’s primary interest lies in the epistemic or justificatory functions of argumentation, then the logical perspective may appropriately be emphasized. If the primary interest lies in the conflict-resolution functions of argumentation, then the dialectical perspective should be emphasized. And if the primary interest lies in the communicative functions of argumentation, then the rhetorical perspective would appropriately be central. If, as seems to be the case, argumentation always has all of these functions to some degree, then no perspective should be emphasized to the complete exclusion of the others. However, the details of what precisely it means to give theoretical priority to one or another of these perspectives remain to be worked out.

4. Conclusion
In the paper that resurrected interest in these three fields as intersecting in the study of argumentation, Wenzel (1980) referred to them as “perspectives.” The implication was that argumentation could be studied from any one of them, and Wenzel’s thesis was that it would be a mistake to consider the study of argumentation to be complete without considering all of them. His view was that, as related to the study of argumentation, logic is concerned with the product of argumentation, dialectic is concerned with the procedures used, and rhetoric is concerned with the process of argumentation. I am not sure he thought that these concerns could be addressed independently of one another. My examinations in this paper seem to support Wenzel’s view that all three perspectives exist in every actual case of argumentation. However, it seems the picture is slightly more complicated than Wenzel envisaged. In the study of arguments and argumentation all three must be considered in relation to one another, but there is more than one type of relationship among them[iv].

[i] The differences between Cohen’s characterizations of logic, dialectic and rhetoric and mine are not great, and immaterial so far as this point goes, I think. For Cohen, “In a purely deductive context, the logical axis could be replaced by a bivalent function, the two values being ‘valid’ and ‘invalid,’ for assessing inferences. But . . . the premises have to be weighed apart from their use in the inference at hand, . . . .  In real-life contexts, logic is better conceived as providing a sliding scale measuring the relevance, sufficiency and acceptability . . . of the premises as reasons for the conclusion” (2001, 74). “An arguer has argued well dialectically when all of the objections and questions that have been raised have been answered satisfactorily” (74-75). “The rhetorical perspective examines the argument’s effects on the audience.  . . . successfully persuading the audience to accept a conclusion is one of the possible effects of an argument” (75).
[ii]  Harvey Strosberg, at the Third International Symposium on Informal Logic, University of Windsor, June, 1988.
[iii] I owe this objection to A.H. van Rees.
[iv] Earlier versions of this paper were presented to WGRAIL (the Windsor Group for Research in Argumentation and Informal Logic) and a graduate class, both at the Department of Philosophy, University of Windsor, the Amsterdam Argumentation Research Group, Department of Speech, Communication, Argumentation Theory and Rhetoric, Universiteit van Amsterdam, and GROLOG (the Groningen Logic group), Filosofisch Instituut, Rijksuniversiteit Groningen. I would like to thank those audiences for their comments and constructive criticisms, all of which influenced the paper in its present form.

Biro, J. and Siegel, H. (1991). Normativity, argumentation and an epistemic theory of fallacies. In: in  F.H. van Eemeren, R. Grootendorst, J.A. Blair and C.A. Willard (Eds.), Argumentation across the lines of discipline (pp. 33-45),  Amsterdam: Sic Sat.
Blair, J.A. and R.H. Johnson (1987). Argumentation as dialectical. Argumentation 1, 41-56.
Cohen, Daniel (2001). Evaluating arguments and making meta-arguments.  Informal Logic 21, 73-84.
Eemeren, F.H. van and Grootendorst, R. (1984). Speech acts in argumentative discussions. Dordrecht: Foris.
Eemeren, F.H. van and Grootendorst, R. (1992). Argumentation, communication and fallacies. Hillsdale, NJ: Lawrence Erlbaum Associates.
Eemeren, F.H. van and Houtlosser, P. (Eds.). (2000a). The relation between dialectic and rhetoric, special issue of Argumentation, 12.2.
Eemeren, F.H. van and Houtlosser, P. (2000b). Rhetorical analysis within a pragma-dialectical Framework. Argumentation 14, 293-305.
Eemeren, F.H. van and Houtlosser. P. (2000c). Argumentation, Interpretation, Rhetoric. Argumentation Online Journal.
Foss, S.K., Foss, K.A. and Trapp, R. (1991). Contemporary perspectives on rhetoric. 2nd ed. Prospect Heights, IL: Waveland Press.
Goldman, A.I. (1985). Relation  between epistemology and psychology. Synthese 64, 29-69.
Goldman, A.I. (1999). Knowledge in a social world. Oxford: Oxford University Press.
Govier, T. (1999). Progress and regress in the dialectical tier. In: T. Govier, The philosophy of argument, Newport News, VA: Vale Press.
Govier, T. (1998). Arguing forever? Or: Two tiers of argument appraisal. In: H.V. Hansen, C.W. Tindale and A. Coleman (Eds.), Argumentation and rhetoric, Proceedings of the 1997 Ontario Society for the Study of Argumentation conference, Brock University, St. Catharines, ON, Canada. CD ROM.
Hansen, H.V. and Tindale, C.W. (Eds.). (1998). Rhetorical considerations in the study of argumentation, special issue of Argumentation 12.2.
Hintikka, J. (1989). The role of logic in argument. The Monist 72: 3-24.
Hohmann, H. (2000). Rhetoric and dialectic: Some historical and legal perspectives. Argumentation 14, 223-234.
Johnson, R.H. (1996). Arguers and dialectical obligations. Unpublished paper presented to the Ontario Philosophical Society, Brock University, St. Catharines, ON, Canada, October.
Johnson, R.H. (2000a). More on arguers and their dialectical obligations. In: H.V. Hansen, and C.W. Tindale (Eds.), Argument at the century’s turn, Proceedings of the 1999 Ontario Society for the Study of Argumentation conference, Brock University, St. Catharines, ON, Canada. CD ROM.
Johnson, R.H. (2000b). Manifest rationality: A pragmatic theory of argument. Mahwah, NJ: Lawrence Erlbaum Associates.
Krabbe, E.C.W. (2000). Meeting in the house of Callias: Rhetoric and dialectic. Argumentation 14, 205-217.
Leff, M. (2000). Rhetoric and dialectic in the twenty-first century. Argumentation 14, 241-254.
Perelman, Ch. And Olbrechts-Tyteca, L. (1958). La nouvelle rhetorique. Paris: Presses Universitaires de France.
Pinto, R.C. (1994). Logic, entailment and argument appraisal. In: R.H. Johnson and J.A. Blair (Eds.), New essays in informal logic (pp. 6-124), Windsor, ON: Informal Logic.
Reboul, Olivier. (1991). Introduction a la Rhetorique. Paris: Presses Universitaires de France.
Tindale, C.W. (1999). Acts of arguing: A rhetorical model of argument. Albany: State University of New York Press.
Wenzel, J. (1980).  Perspectives on argument. In: J. Rhodes and S. Newell (Eds.), Proceedings of the 1979 Summer Conference on Argumentation, Falls Church: SCA.
Woods, J. (1995). Fearful symmetry. In: H.V.  Hansen and R.C. Pinto (Eds.), Fallacies: Classical and contemporary readings (pp. 181-193). University Park, PA: The Pennsylvania State University Press.