ISSA Proceedings 2006 ~ Pragma-Dialectics And The Function Of Argumentation

logo 20061. Introduction: Pragma-Dialectics and the Aims of this Paper
During the last 25 years Frans van Eemeren and Rob Grootendorst have very impressively developed Pragma-Dialectics, i.e. a consensualistic theory of argumentative discourse, which sees the elimination of a difference of opinion as the aim of such discourses and of argumentation. Currently this is the most famous and most discussed approach in argumentation theory in the world.

In what follows I will discuss Pragma-Dialcetics mainly from an epistemological standpoint, i.e. what this theory has to tell us with respect to acquiring true or justified beliefs and knowledge.

Technical note: The discussion rules are the constructional core of Pragma-Dialectics; in addition to a few material changes and to stylistic improvements, these rules have undergone a change in numbering. In this text I will refer to their first English version (E&G 1984, p. 151-175) as “Ro1” etc. (“original (or old) rule no. 1”) and to their most recent statement (E&G 2004, pp. 135-157) as “Rs1” etc. (“Rule in ‘Systematic Theory of Argumentation’ no. 1”). The material changes regard, first, the possibilities of defending (or attacking) a premise (Ro9/Rs7 (E&G 1984, p. 168; 2004, p. 147 f.)); the originally included possibility of common observation has been deleted – which is surprising – and the originally lacking possibility of argumentatively defending a premise included, which is a clear improvement. The second and most important change concerns the argument schemes that may be used for defending a claim: originally only deductive arguments were permitted now non-deductive argument schemes have been added (Ro10/Rs8 (E&G 1984, p. 169; 2004, p. 150)) – a substantial improvement. The following discussion usually refers only to the best version.

2. The Aim of Argumentation and Argumentative Discourse: Elimination of a Difference of Opinion
The whole approach of Pragma-Dialectics is constructed starting from one central theorem about the function of argumentative discourse and argumentation in general. The aim of argumentative discourse and of argumentation, as these are seen and constructed by Pragma-Dialectics, is to eliminate a difference of (expressed) opinion (e.g. E&G 1984, p. 1; 1992, xiii; p. 10; 2004, pp. 52; 57; Eemeren et al. 1996, p. 277) or to resolve a dispute – where “dispute” is understood as: expressed difference of opinion (e.g. E&G 1984, pp. 2; 3; 151). This resolution has taken place if the participants both explicitly agree about the opinion in question. The central task of the theory is to develop rules for rational discussions or discourses; and the value of the rules to be developed is regarded as being identical to the extent to which these rules help to attain the goal of resolving disputes (E&G 1984, pp. 151; 152; cf. 2004, pp. 132-134).

This, obviously, is a consensualistic conception of argumentative discourse and of argumentation, which aims at an unqualified consensus, i.e. a consensus that is not subjected to further conditions.[i] Consensualism defines a clear aim for argumentation and argumentative discourse, which can be the basis for developing a complete argumentation theory, including criteria for good argumentation, good discourse, theory of fallacies, theory of argumentation interpretation, etc. Thus, consensus theory in general, and Pragma-Dialectics in particular, is a full-fledged approach to argumentation theory. Similar and competing full-fledged approaches are, first, the rhetorical approach, which sees convincing an addressee, i.e. creating or raising an addressee’s belief in a thesis, as the aim of argumentation (e.g. Perelman & Olbrechts-Tyteca 1958; Hamblin 1970; Tindale 2004), and, second, the epistemological approach, which sees generating the addressee’s justified belief in the argumentation’s thesis as the standard function of argumentation (e.g. Biro & Siegel 1992,; Feldman 1994; Goldman 1999, ch. 5; Johnson 2000; Lumer 1990; 1991; 2005/2006; Siegel & Biro 1997). As opposed to epistemological theories, both consensus theory and rhetoric aim at an unqualified belief (though in Pragma-Dialectics this is more an expression of a belief than the belief itself); but consensus theory then, unlike rhetoric, requires that both participants share this opinion.

It is quite astonishing that even though Van Eemeren and Grootendorst repeat their aim for argumentative discourse, i.e. dispute resolution, countless times, they practically do not justify this most central assumption of their approach. They incidentally justify the need for dispute resolution with the remark that “otherwise we become intellectually isolated and can ultimately even end up in a state of spiritual and mental inertia” (E&G 1984, p. 1). However, “not being intellectually isolated” could be an euphemism for “conformism”. Of course, not being intellectually isolated is good; but it is of secondary importance. It is much more important that one’s beliefs are true (and justifiedly true) and thus can help one orient herself or himself in the world. Intellectual isolation could simply be the price of truth, or more precisely, of justified true beliefs that others are not able or not willing to understand or accept – think of Galileo or Frege.

So what is the problem with conflicting beliefs and why is it important to resolve differences of opinion? The most simple and straightforward answer is: At least one of these opinions must be false. And having false opinions means having a false and disorienting picture of the world, which e.g. makes us miss our goals. What is completely missing in Pragma-Dialectics is any systematic relation to truth or its epistemological counterparts, knowledge and justified belief. Pragma-Dialectics has this in common with rhetorical approaches. Aiming at unqualified beliefs or shared beliefs that are not systematically related to truth in the sense that they are true or (because of the epistemologically founded cognizing procedures used) at least acceptable in the sense of being true, probably true or truthlike, of course, leads to much less true or truthlike beliefs than aiming at justified beliefs. The consequence is much less orientation and more disorientation about the world’s real state, which, finally, leads to more grossly suboptimum or even disastrous decisions. This was already Socrates’ and Plato’s critique of rhetorical argumentation theory (e.g. Plato, Phaidros 259e-262c; Gorgias 452e-455d; 458e-460a; Philebos 58a-59b). To aim at unqualified consensus instead of unqualified belief of a single person does not make the situation any better because truth does not depend on anyone sharing it but on objective fulfilment of truth conditions. Of course, an unqualified consensus can be true; but it would be true by chance and thus not reliable.

Let me extend the discussion by considering consensus theory in a more general form. The problem with normative consensus theories of argumentative discourse is not that they aim at consensus but that they take an unqualified consensus to be the aim of such discourse. Theories of argumentative discourse have also been proposed in epistemological argumentation theories, which see such discourses as enterprises for collectively seeking truth (Goldman 1999, pp. 139-149; Lumer 1988). Even in these theories the internal end of the game is to reach consensus. But it is a qualified, justified consensus, where both parties not only share the final opinion but – ideally – also their subjective justification for it. To take justified consensus as the aim of argumentative discourse avoids all the problems listed so far because justification – correctly conceived – is related to truth. It is based on cognizing procedures that guarantee the truth or at least the acceptability, i.e. truth, high probability or verisimilitude, of the results. What I would suggest to Pragma-Dialecticians then is to adopt justified consensus as the aim of argumentative discourse.

3. Elements of Epistemic Rationality in Pragma-Dialectical Discourse
Actually, Pragma-Dialectics is much nearer to the suggestion just intimated than it may at first, and in particular as a consequence of its determination of the goal of argumentation and argumentative discourse, appear. This is so due to a continuous incoherence in Pragma-Dialectics, namely the inclusion of important elements of epistemic rationality in its consensualistic programme. This incoherence is most evident in the Pragma-Dialectical rules for argumentative discourse.

Completely in line with the just criticized unqualified consensualistic determination of discourse’s aim as dispute resolution, as their criterion for good discourse rules Van Eemeren and Grootendorst establish that such rules have to promote that aim. Strangely enough, Van Eemeren and Grootendorst never go on to prove that the rules they propose are the best in these terms. And actually these rules are not developed consequently along these lines but according to a vague idea of a rational discourse that includes many elements of epistemic rationality. As a consequence, Pragma-Dialectics is a hybrid theory, mixed of incompatible elements of unqualified consensualism and epistemic rationality.

Let us take a closer look at this inconsistency. As Goldman nicely caricatures, the most effective way to reach unqualified consensus may be to engage a professional mediator, whose secret strategy would consist in finding out which party is more prone to make concessions and then to canvass this party for pulling it in the opponent’s direction (Goldman 1999, pp. 159 f.). Other means for reaching unqualified consensus include rhetorical and psychological tricks, eristic devices, a strategy of friendly offers and giving up one’s own opinion (this is particularly efficacious if only verbal consensus is what counts). None of these means will be the one that is best in all situations, however the best strategy for reaching unqualified consensus probably will include them all, each for particular situations.

Actually, Van Eemeren and Grootendorst do not include any of these means in their list and even explicitly oppose rhetoric (E&G 1992, p. 5). This is due to their strong claims of rationality. However again it is typical of Pragma-Dialectics that these claims are ambiguous. On the one hand there are purely verbal claims of rationality, which at a closer look turn out to be merely consensualistic or rhetorical. On the other hand there are many elements of real epistemic rationality in the Pragma-Dialectical theory in general and in its discourse rules in particular.

One example of a merely verbal declaration for epistemic rationalism is this. Van Eemeren and Grootendorst declare: “Argumentation is […] designed to justify […] an expressed opinion and calculated […] to convince a rational judge […]” (E&G 1984, p. 18; the emphasis is mine, C.L.; similar: ibid. p. 9; 2004, pp. 1; 10; 12 f.) But then they define this ‘rational judge’ simply in consensualistic terms as someone who follows such acceptable rules “which can lead to a resolution of the dispute” (E&G 1984, p. 18; cf. p. 5; 2004, pp. 16; 17 f.; 132).

On the other hand Pragma-Dialectics contains clear and strong epistemologically rational elements. A first such element is the prescription of a certain argumentative structure as the obligatory way to consensus, namely the use of argumentation, premises and inferences (Ro9-11/Rs7-9 (E&G 1984, p. 168; 2004, p. 148); more generally: E&G 1992, pp. 34; 158 f.; 169; 184-194). A second element is the strong use of logic and deductive arguments in the argumentation stage of discourse. A third rational element is the use of joint observation as part of the intersubjective testing procedure (E&G 1984, p. 167) and of statistical arguments (E&G 1992, p. 96; 2004, p. 150, note 20) again in the argumentation stage. But, unfortunately, again Van Eemeren and Grootendorst relativize even these clear elements of epistemic rationality in a consensualistic fashion. They see these elements as their personal proposals, which in order to be valid would then have to be jointly adopted by the respective discussants (E&G 1984, p. 163; 2004, p. 142). Thus, Pragma-Dialectics’ final determination of the aim of argumentative discoures amounts to unqualified consensus in a broader sense: the consensus about the claim in the end is subjected to rules, but now these rules depend only on an unqualified consensus (cf. note 1).

4. Some Philosophical Sources of Pragma-Dialectical Ideas of Epistemic Rationality
On the whole the writings of Van Eemeren and Grootendorst show a strong inclination towards standards of epistemological rationality, which then are corrupted by their adherence to unqualified consensualism. One reason why these two elements have not been brought together in a more satisfying way, specifically by taking justified consensus as the aim of rational discourse, may be the particular theories of epistemic rationality used by Van Eemeren and Grootendorst, namely Critical Rationalism and the Erlangen Constructivism, especially Lorenzen’s Dialogic Logic. Both these theories contain quite confused parts, which have been adopted by Van Eemeren and Grootendorst.

From Critical Rationalism they have taken in particular Albert’s critique of justificationism by his “Münchhausen-Trilemma”, which says that the attempt to justify every belief must lead to one of three bad alternatives,
(1) an infinite regress,
(2) a logical circle or
(3) arbitrarily and dogmatically breaking off the justification (Albert 1980, pp. 10-15; referred to by Van Eemeren and Grootendorst: E&G 1984, pp. 16; 194, note 9; 2004, p. 131).

The Münchhausen-Trilemma for Van Eemeren and Grootendorst is the reason, first, to give up the idea of positive justification and, second, to bet on negative criticism instead and thereby on dialectics, i.e. the inclusion of other persons, critics, as necessary elements in the process of epistemic rationality (E&G 1984, p. 16; 2004, pp. 131 f.). This decision seems to have been their main reason for not seeking further positive forms of arguments beyond deductive ones and to stress the unforeseeable critical potential of an antagonist instead. And this, as will soon be shown, is one of the main weaknesses of Pragma-Dialectics. Now the Münchhausen-Trilemma is simply false.[ii] It rests on a hidden and false premise, namely that deduction from true premises is the only form of acceptable justification. Together with the well-known properties of deductive justification, namely, first, to presuppose already justified premises and, second, to maximally preserve, mostly to reduce but never to increase the informational content of the justified conclusion compared with the premises, that premise leads to the exposed trilemma. But of course, there are forms of justification that do not rely on already justified premises, in particular observation; and there are ampliative forms of justification (i.e. forms of justification that increase the thesis’ informational content), in particular inductive reasoning. Thus there is no need to give up justificationism, on the contrary, and non-deductive forms of monological argumentation have to be studied and reconstructed in argumentation theory.

From Lorenzen’s and the Erlangen School’s theories in general Van Eemeren and Grootendorst have adopted the Dialogic Logic as their own conception of logic. They approve this logic for its dialogical, communicative and interactive character (E&G, pp. 12; 14; 193, n6; 2004, p. 50) as well as its enlargement by Barth & Krabbe (E&G 1984, p. 193, n6; 2004, pp. 50 f.), they use this logic themselves (e.g. E&G 1984, pp. 12-15) and they suggest it as the central tool in deductive argumentation (E&G 1984, p. 169; 2004, p. 148; Eemeren et al. 1996, p. 274). There are four elements of the Erlangen School’s programme and Dialogic Logic that are relevant in our context:
(1) logical intuitionism,
(2) anti-platonism,
(3) constructivism and
(4) the dialogical conception of logic.
Van Eemeren and Grootendorst are interested in these elements in ascending order. All four elements are highly problematic. However, limitation of space allows me to show this for only two of them, constructivism and the dialogical conception of logic.

(3) “Constructivism” means that all reasoning schemes and terms have to be explicitly introduced and that all reasoning steps like the introduction of premises and pieces of inferences have to be explicitly executed. The correct ideas behind constructivism are clarity and – in particular in mathematical contexts – avoidance of illusory “short-cuts” in reasoning. But constructivism is an exaggeration of these ideas, which, first, ignores that in discourses we can and must rely on a shared language and common knowledge. It would be absurd each time to try to “introduce” our complete vocabulary and common knowledge. The much more feasible and efficient way is knowledge exploitation, i.e. to rely on these common bases as far as one thinks they reach in the specific case, to make language usage explicit when one thinks that there could be ambiguities, to make premises explicit when they are used etc. Second, in its mania for explicit introducing and agreements, constructivism has a strong tendency towards a false form of conventionalism, namely to regard inference, reasoning and argumentation rules as something that is valid by convention and not as objective truths. If the meaning of logical operators and of terms is conventionally fixed, given the actual world, propositions’ truth thereby is fixed as well. Whether certain inference schemes lead from true premises to true conclusions then is no longer a question of convention but of analytical truth; analoguous considerations hold for uncertain ways of reasoning. And whether a given addressee already accepts particular premises and reasoning schemes is an empirical question.

(4) Dialogic Logic is a kind of logic that conceives logical proofs as dialogue games, where a proponent “defends” his thesis in an exactly regimented way against an opponent’s “attacks” by logically decomposing it into elementary formulas already accepted by the opponent (cf. e.g. Kamlah & Lorenzen 1973, pp. 209-231; Lorenzen & Schwemmer 1975, pp. 56-147). Dialogic Logic probably is the most confusing element of the Erlangen programme. Its origins are Beth’s semantic tableaux, i.e. a semantic way of proving an inference’s logical validity. You take a sheet of paper and divide it into a left and a right half by drawing a vertical line down the middle. The left half is reserved for the true propositions and the right half for the false propositions. The aim of the procedure is to systematically search for a consistent interpretation of the inference in question that shows it, the inference, to be invalid. This is an interpretation where the premises are true and the conclusion is false. If you do not find such an interpretation, the inference is valid. So at the top of the left column, i.e. the truths side, you write the premises, and at the top of the right, i.e. the falsities side, you write the conclusion. Premises and conclusions then have to be decomposed into elementary formulas, according to logical rules. If in the end the same elementary formula appears on the left as well as on the right side, this means that this formula has to be true and false at the same time. So it was impossible to construct a consistent falsifying interpretation of the inference (i.e. an interpretation where the premises are true but the conclusion is not). Therefore, the inference is valid. (In figure 1.1. this is illustrated with a simple example: the inference ‘p => q->p‘ is scrutinized for its logical validity. For disproving its validity one has to find an interpretation where the premise p is true – therefore p appears in row 1 on the truths side – and the conclusion q -> p is false – so q -> p appears on the falsities side. For q -> p to be false q must be true and p false; therefore the false q -> p of row 1 in row 2 is decomposed into a true q and a false p. But now p appears on the falsities side (in row 2) as well as on the truths side (in row 1), which means that to make the inference invalid p must be true and false at the same time, which is impossible. Therefore, the inference is valid.) This is a pencil-and-paper test that can be executed by one person; all the steps are exactly prescribed. Now some sequences of steps in semantic tableaux resemble sequences of turns in an argumentative dialogue. This has led Lorenzen and Lorenz (in the late 1950s and the 1960s) (reprints: Lorenzen & Lorenz 1978) to interpret the semantic tableaux as a dialogue game and to assign the right, falsities side, which contains the conclusion, to a “proponent”, and the left, truths side, which contains the premises, to the “opponent”, where the premises now are mutated to the opponent’s concessions (cf. figure 1.2).[iii] This is a nice gewgaw as long as one is aware of the theoretic background. But it is heavily confusing when the dialogic nature is taken seriously, and the “Dialogic Logic” is taken as proof that logic is something dialogical. And it is confusing because many sequences in logical dialogue games do not make sense in a real argumentative discourse – because they have a quite different function. Why for example may ¬p only be attacked by claiming p and not by asking for a justification?[iv] Actually, Dialogic Logic contains nothing really dialogical, one and the same person can play both roles because all the steps to be executed are meticulously prescribed.[v] And of course, logical reasoning can be executed internally by one person by proceeding from a belief in some premises, recognizing a logical implication, to believing in the conclusion.

Figure 1.1: Semantic tableaux: Is 'p => q -> p' valid?

Figure 1.1: Semantic tableaux: Is ‘p => q -> p’ valid?

Now Van Eemeren and Grootendorst have adopted Dialogic Logic as their favourite logic (E&G 1984, pp. 169; 201, note 68; 2004, p. 148; Eemeren et al. 1996, p. 274). This is harmless to a certain degree. But it is terribly misleading if Dialogic Logic is taken seriously and regarded as a proof of the necessary dialogic character of argumentation (E&G 1984, pp. 12-14; 193, note 6). Actually, argumentation (in the sense of “presenting an argument”) is mostly a monologic activity, where someone argues for a certain thesis.[vi] And argument schemes have to be developed on this basis. A systematically second step then is to develop a theory of argumentations’ integration into argumentative discourse. Fortunately, Pragma-Dialectics has not taken its theoretical profession of the necessary dialogical character of argumentation too seriously; in the official definition (E&G 1984, pp. 7; 18; 2004, p. 1), in the discussion rules (e.g. Ro8/Rs6, E&G 1984, p. 165; 2004, p. 144) and in analytic practice argumentation is always conceptualized monologically (in the sense explained in note 6) as the protagonist’s advancing his thesis plus his defensive moves. Nonetheless the theoretical assumption of the necessary dialogic character of argumentation may have been one of the reasons for Pragma-Dialectics’ neglecting argumentation theory in the narrow sense, specifially for neglecting the study of non-deductive argument schemes.

One of the lessons that could be learned from these scathing criticisms of Pragma-Dialectics’ epistemological foundations is that much could probably be improved by changing the epistemological basis of Pragma-Dialectics. Pragma-Dialectics is mainly a theory of argumentative discussion and not of (monological) argumentation. Combining it with the epistemological theory of argumentation and its epistemological foundations could already be the beginning of important progress.

5. The Procedural Rules for a Critical Discussion
The constructive core of Pragma-Dialectics are the rules of conduct it proposes for critical discussions. In this section, the real discourse rules, i.e. the rules for integrating argumentation in discourses, will be discussed; the next section is dedicated to the rules for the argumentative core.

The Pragma-Dialectical discourse rules are designed for simple, i.e. single and nonmixed, discussion (originally called: “simple single discussion”), in which exactly one thesis (not even its negation) is discussed (E&G 1984, p. 152; 2004, p. 135; terminology: E&G 1992, pp. 16-22). This implies that the antagonist can accept the protagonist’s thesis, or express non-acceptance or can ask for a justification, but he cannot advance an incompatible counter-thesis, specifically he cannot say that the protagonist’s thesis is false. The same limitation holds for the antagonist’s “attacks” on the single reasons and the argumentative relation between reasons and thesis. This means real, offensive attacks are missing.[vii] And therefore the antagonist cannot point to the protagonist’s errors; no real critique is taking place. As a consequence the discussants cannot obtain certification of their respective theses by having them exposed to intersubjective critique. In addition, the antagonist cannot contribute his own knowledge to a cooperative search for truth. So the most important aims of a real discourse cannot be reached by Pragma-Dialectical “discourses”. Pragma-Dialectical discourses are not really dialogical discussions. They are monological argumentations enlarged by possibilities to adapt this argumentation to the addressee’s epistemic situation. Ironically enough, Van Eemeren and Grootendorst here have completely set aside the criticism of Critical Rationalism, which, of course, requires refutations by positive counter-evidence, and returned to justificationism. And again ironically enough, epistemological argumentation theories, often decried for their monological conception of argumentation, compared to Pragma-Dialectics are much more and only really dialogical when it comes to integrating argumentation in argumentative discourse (cf. Goldman 1999, pp. 139-149; Lumer 1988).

Under procedural aspects Ro7/Rs5 (E&G 1984, pp. 163 f.; 2004, p. 143) is the most irritating rule. It quite innocently requires that, in the preparation stage the discussants agree about the rules that shall govern and be binding for the entire discussion that follows. Only subsequent rules, in particular Ro9/Rs7 and Ro10/Rs8, reveal how many agreements are meant to be included: agreement about the intersubjective identification procedure (for identifying shared premises), the intersubjective testing procedure (which regiments observation (E&G 1984, p. 167) and the use of non-deductive argument schemes (E&G 2004, pp. 149 f.), respectively), the intersubjective explicitization procedure (for making implicit premises explicit), the intersubjective reasoning procedure (i.e. the deductive logic) and the premises themselves as well (E&G 1984, pp. 165 f.; 2004, p. 145). In order to be fully consistent with this logic of agreements, rules Ro8/Rs6 to Ro17/Rs14 should have been included in that list. Of course, this list should have been made explicit in Ro7/Rs5.

These agreement requirements are a heritage of constructivism, which in general has already been criticized (section 4). Some more specific problems are the following. First, the agreement requests are illusory, people cannot make all these things explicit and do not have the time to try to do so. Second, the agreement requirement is a simple fiat; nothing is said about how it could be reached. Considering that it includes encyclopedias, logics, epistemologies etc. it is not to be expected that discussants find an agreement. Third, an initial agreement is too rigid. The discussants may change their opinion about one or the other point. – Van Eemeren and Grootendorst seem to have seen some of these problems and therefore provide that the discussants commonly “assume tacitly that they accept more or less the same rules for the discussion” (E&G 1984, p. 163; similar: 2004, p. 142) and a common knowledge (E&G 1984, p. 166; 2004, p. 146). But if this is so and if constructivism is illusory, they should give up the constructivist rule Ro7/Rs5 altogether and adopt the concept of knowledge exploitation. And because knowledge exploitation is not trivial this requires the introduction of new substantive rules about how to make assumptions about the other discussant’s knowledge, what to do if such assumptions are false etc.

6. The Argumentation Rules for a Critical Discussion
The second part of my discussion of the Pragma-Dialectical discourse rules regards the rules for the argumentative core, its argumentation theory proper.

In a perfect consensualistic fashion, Pragma-Dialectics conceives argumentation rules as something that must be agreed upon by the discussants, i.e. as conventions (E&G 1984, p. 163; 2004, p. 142). And consequently, the Pragma-Dialectical argumentation rules are advanced only as proposals for such conventions, without which they would not have any validity (ibid.). But what is the aim of such conventions? According to Pragma-Dialectics, it is to resolve differences of opinion. However the question can be repeated, why should people try to do so? In particular if one speaks of expressed opinions only, one could introduce such conventions like rules of an entertaining game like chess, where one finally arrives at an explicit but meaningless “consensus”, which has nothing to do with one’s opinions. Of course, Van Eemeren and Grootendorst do not want this. Why should we want a real consensus? Convincing someone of a particular thesis in a rhetorical vein may have strategic advantages, but why should the arguer want to share this opinion? Pragma-Dialectics is silent about these questions; it simply does not contain a theory about the function of argumentation and about the way in which this function can be fulfilled by argumentation. And without such a function analysis argumentation rules will be arbitrary or only accidentally useful.

The straightforward answers to these questions are epistemological; and the usually recognized argumentation rules can best be explained epistemologically. The function of argumentation is to provide justified belief, which is systematically (though not strictly) connected to truth (Lumer 2005a, sect. 4; 2005b, sect. 1); and shared justified belief is a greater guarantee that this belief is really true. Argumentations help to achieve justified belief by guiding an addressee’s cognizing the thesis etc. (Lumer 2005a, sect. 5; 1990, pp. 45-48; 280-281; 1991, pp. 102-104). If one adopts this epistemological function analysis of argumentation, argumentation rules cannot simply be conventions. As Siegel, Biro and Goldman have already criticized, agreeing on fallacious argumentation rules like the gambler’s fallacy or plainly absurd or arbitrary argumentation rules like admitting only arguments with an even number of premises, simply does not lead to true or at least acceptable belief (Biro & Siegel 1992, p. 91; Goldman 1999, p. 159). Argumentation rules have to fulfil two essential functions, first, following them should guarantee the thesis’ truth or acceptability, i.e. truth, high probability or verisimilitude, and second, following them should provide epistemic accessibility of the truth (or acceptability) to the addressee, e.g. by requiring that the premises be known to the addressee. If a particular set of argumentation rules fulfils these functions does not depend on convention but is an objective fact – like the functioning of a machine; it depends e.g. on how these rules refer to theses’ truth conditions. Someone can find out these rules, follow them for the first time in trying to convince a particular addressee who does not know anything about these rules, and they could still fulfil their function. Think for example of rules for logical deduction. Whether such rules always lead from true premises to true conclusions depends on the definitions of truth functional operators, which determine the truth-value of complex propositions dependent on the truth-value of elementary propositions; given such definitions it is not a question of agreement. Independence of agreement makes monological argumentation possible and, of course, facilitates discourses; the bulk of the Pragma-Dialectical opening stage becomes superfluous.

What just has been said about argumentation rules analogously holds for premises or, more generally, for reasons too. Pragma-Dialectics is completely consensualistic here in prescribing only shared acceptance of premises (Ro9/Rs7 (E&G 1984, p. 168; 2004, p. 147) and E&G 1984, pp. 165 f.; 2004, p. 145). But, of course, such consensus does not imply the premises’ truth or acceptability.

Originally, Van Eemeren and Grootendorst proposed only one type of argumentation, namely deductive argumentation (cf. Ro10/Rs8 (E&G 1984, p. 169; 2004, p. 150)) – which has been criticized e.g. by Pinto (Pinto 2001, p. 133). More recently Van Eemeren and Grootendorst also included some further argument schemes (E&G 1992, pp. 94-102; 2004, pp. 149 f.; 150, Rs8), namely:
(1) symptomatic argumentation of the form ‘a is F; F‘s are typically G; therefore a is G‘;
(2) comparison argumentation or argumentation by analogy of the form ‘a and b are similar or analogous; a is F; therefore b is F’; and
(3) instrumental argumentation with the form ‘p is F; events of type F cause events of type G; therefore there will be an event of type G‘ (E&G 1992, pp. 96 f.).

However, this is not much of an extension of the theory of argument schemes. Symptomatic arguments are a particular type of probabilistic arguments (with a sure singular and a statistical premise); analogies are good heuristic devices but, because of the unclear extension of the analogy, bad arguments; instrumental arguments, finally, are only particular forms of deductive arguments. So these additional argument types are too special, and the resulting list of argument types is very unsystematic. But the major problem is that still most argument types are missing: probabilistic and statistical arguments in general, theoretical arguments for empirical theories and theoretical theses, practical arguments for value judgments etc. (cf. Lumer 2005b, sect. 3). These problems at least in part are due to the lack of a function analysis of argumentation in Pragma-Dialectics.

Let me sum up some major results of this discussion of Pragma-Dialectics.
(1) Its two main aims make Pragma-Dialectics a heterogeneous theory composed of unqualified and therefore unsatisfactory consensualism and an ill-conceived form of epistemic rationalism. A better synthesis of the useful parts of these ideas would be to take justified consensus as the aim of argumentative discourse.
(2) Pragma-Dialectics relies on very problematic epistemologies, namely Critical Rationalism and Dialogic Logic. Pragma-Dialecticians should look for a better partner in this field.
(3) The procedural rules for a critical discussion are a strong point of Pragma-Dialectics. But they should be expanded to rules for a complete discourse and be corrected in several details with an eye on the function of argumentative discourse, i.e. to cooperatively search for truth and to certify justified beliefs by exposing them to intersubjective criticism.
(4) The rules for argumentation proper are a weak point of Pragma-Dialectics. This is due to the unqualified consensualism and to the lack of a function analysis of argumentation. Epistemological argumentation theories have much more to offer in this respect. Thus they could provide the necessary complement to the procedural rules, which are a strong point of Pragma-Dialectics.

Acknowledgements: I would like to thank several people for discussion and helpful hints: Michael A. Gilbert, Ralph Johnson, Erik Krabbe, Martin Reisigl, Harvey Siegel, Harald Wohlrapp and Frank Zenker.

NOTES
i. As we will see in the following section, in a systematically later stage Pragma-Dialectics goes beyond this initially fixed aim and requires that the dispute resolution be reached by a regimented discussion. But even the consensus resulting from these discussions is still unqualified in a broader sense, namely in the sense that now the discussion and argumentation rules governing the discussion as well as the premises to be used are established by an unqualified consensus which is not subject to further conditions – e.g. epistemic principles (cf. E&G 1984, pp. 163-168, in particular Ro7; 2004, p. 143, Rs5).
ii. For a detailed criticism of Albert’s Münchhausen-Trilemma see: Lumer 1990, pp. 197-209.
iii. Lorenzen himself originally admitted that his own dialogical notation, apart from the question marks, is exactly identical to Beth’s semantic tableaux (Lorenzen 1959/1961 in: Lorenzen & Lorenz 1978, p. 11). Subsequently Lorenzen and his followers have hidden this connection.
iv. Some further examples of Dialogic Logic’s rules that make no sense in argumentative discourse are given in: Lumer 1988, p. 446.
v. A more extensive criticism of Dialogic Logic on these lines is given in: Lumer 1990, pp. 317 f. In particular, some members of the Erlangen School are quoted who later dissociated themselves from the dialogic conception of logic.
vi. Please note that “monologic” is meant here only in the weak sense, i.e. that one and the same person presents the whole (perhaps complex) argument. It is not meant in the strong sense that only one person is speaking during the conversation. The intended weak sense of “monologic” does not exclude that the arguer’s presentation of his argument be distributed over several turns in a dialogue and interrupted by the questions or objections of another speaker. However, usually such questions and objections mainly have the function of fitting the argument to the addressee; but it remains the arguer’s argument.
vii. In my own model of argumentative dialogues groups of possible moves are distinguished: A-moves, which allow argumentation, B-moves, which include agreements and requests of justification by the opponent, C-moves, which allow the opponent’s attacks, etc. (Lumer 1988, pp. 450-457). Pragma-Dialectical discourses correspond to what I have called “simple argumentative dialogue”, which consists of A- and B-moves only (Lumer 1988, p. 454); in particular equivalents to the C-moves are missing.

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