STUDIES IN LOGIC, GRAMMAR AND RHETORIC 23 (36) 2011

Jacky Visser
University of Amsterdam & International Learned Institute for Argumentation Studies

Floris Bex
University of Dundee

Chris Reed
University of Dundee

Bart Garssen
University of Amsterdam & International Learned Institute for Argumentation Studies

CORRESPONDENCE BETWEEN
THE PRAGMA-DIALECTICAL DISCUSSION MODEL
AND THE ARGUMENT INTERCHANGE FORMAT

Abstract: The pragma-dialectical ideal model of a critical discussion takes
a normative approach to argumentative discourse. The model defines the fourstages of a critical discussion, conditions on speech acts and their distribution over the stages, and a set of 15 procedural rules regimenting the moves
discussants may make. These problem-valid rules are instrumental towards thereasonable resolution of the difference of opinion. We take the model of a critical
discussion as constituting a basis for a dialogue protocol allowing agents to playout a dialectical game in order to test the tenability of one agent’s standpoint.
The Argument Interchange Format (AIF) allows such a dialogue protocol to
be translated in terms of its core ontology. The core ontology provides a directed graph data structure in which descriptions of argumentative discourse andarguments can be represented. The AIF can function as interlingua allowing
various frameworks and theories of argumentation to interact in theoreticallyunbiased terms. Establishing a correspondence between pragma-dialectical notions and the AIF would provide the latter with a normative natural language discussion model. Furthermore viewing the pragma-dialectical theory froma formalised perspective indicates possible areas of concern which need to beaddressed before the theory could get involved further in the field emerging on
the intersection between argumentation theory and artificial intelligence.
Keywords: Argument Interchange Format, critical discussion, dialogue protocols, Pragma-Dialectics

1. Argumentation and theory
In the last forty years the pragma-dialectical approach to argumentative
discourse has been developed into a full-blown argumentation theory andnormative discussion model. (van Eemeren and Grootendorst 1984; 2004)
The theory takes any argumentative exchange as an instantiation of theISBN 978–83–7431–***–*ISSN 0860-150X

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Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
ideal model of a critical discussion. This allows the discourse to be analysed, reconstructed and evaluated with respect to a normative model. Starting out as a theory based on speech acts as the functional building blocksof linguistic communicative activity (“pragma”, short for pragmatics, being the ﬁeld within linguistics in which meaning is regarded as inherently
context-dependent) and a procedure for reasonably resolving a diﬀerence of
opinion (taking the “dialectical” perspective), it has since been extended toalso incorporate rhetorical aims of eﬀectiveness and institutional contexts
among others. (van Eemeren 2010) Lately the conventional validity – whether the restrictions in the normative model match accepted conventionsin actual use – of the theory has also been put to the test in a series of
empirical studies. (van Eemeren, Garssen and Meuﬀels 2009)
In the past few decades, AI has developed its own sub-ﬁeld devoted tocomputational argumentation theory, in which signiﬁcant theoretical andpractical advances are being made. This fecundity, unfortunately, has a negative consequence: with many researchers focusing on diﬀerent aspects ofargumentation, it is increasingly diﬃcult to reintegrate results into a coherent whole. To tackle this problem, the AI community has initiated an eﬀort
aimed at building a common ontology for computational argument, which
will support interchange between research projects and applications in thearea: the Argument Interchange Format (AIF). (Chesñevar et al. 2007)
Thus far there has been notably little interaction between computational
argumentation theory and the pragma-dialectical approach. In the present
paper we will focus on this disciplinary intersection by presenting a preliminary account of the correspondence between the standard pragma-dialecticalmodel of a critical discussion and notions within the AIF.1 The rules fora critical discussion within the context of the ideal pragma-dialectical discussion model can be taken as constituting the foundations for a dialogue
protocol. A justiﬁcation for the possibility of ‘protocolisation’ of the rules
can be found in their instrumentality towards the goal of the discussion –i.e. reasonably resolving the diﬀerence of opinion. Any move in violation of
the rules would obstruct the resolution and would therefore be fallacious. By
following such a protocol agents can play a dialectical game in which theydecide on the acceptability of a certain proposition in a reasonable manner.
Developing the protocol gives us the opportunity to further investigate
the rules for critical discussion on the coherence and consistency of the pro1 The standard pragma-dialectical model refers to the theory before its rhetoricalextension in terms of strategic manoeuvring. See (van Eemeren and Grootendorst 2004)
for the standard model and (van Eemeren 2010) for the extended.

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Correspondence between the Pragma-Dialectical Discussion Model and...
cedure proposed. As such we can investigate the problem-validity of the rulesby testing whether all of the rules are actually aimed at the goal of resolving
the diﬀerence of opinion and whether there are no additional rules necessary
to ideally avoid moves that distract from reaching the overall goal.2 Becauseof the AIF’s links to more formal systems, translating the protocol into thelanguage of the AIF opens up the possibility of actually implementing thedialectical game of a critical discussion in established computational applications and algorithms at a later moment. These can range from tools tovisualise argumentation to automated decision-making systems, and fromother dialogue games to logical systems that decide on the validity of arguments. From a computational point of view taking pragma-dialecticalinsights into account can provide a normative foundation to some applications and answer questions such as those raised by McBurney and Parsons(2009) about the design and assessment of dialogue protocols:“How many locutions should there be? What types of locutions should be
included, e.g., assertions, questions, etc? What are the appropriate rules for the
combination of locutions? When should behavior be forbidden, e.g., repeatedutterance of one locution? Under what conditions should dialogues be madeto terminate?” (p. 275)

Being a normative discussion model the pragma-dialectical theory provides
a procedure which regiments moves in deliberative or persuasive dialogues
in multi-agent systems. It also presents us with a fully developed overview ofadmissible locutions and argumentative moves, a speech act based approachthat allows for complex, composite speech acts, a notion of discussion stages,of fallacious moves, etc.
The current paper investigates the groundwork of an addition of thepragma-dialectical theory of argumentative discourse to the AIF arsenal asa natural language discussion module. For now we start with a very basic
instantiation, creating the opportunity to expand on it in the future. Besides
possibly simplifying the theory at points (by, for example, only focussing on
single non-mixed diﬀerences of opinion – more on which later), we currently steer clear of the rhetorical extension with strategic manoeuvring, theinstitutional embedding with argumentative activity types and the analysis of argumentative discourse through the use of linguistic indicators anddialectical proﬁles. (See respectively van Eemeren 2010, and van Eemeren
2 This is not to say that any problems found would actually be problems to the theory
because the specific issue might be addressed in another part of the theory. It could point
us towards aspects of the rules that are less well-developed from a formal perspective.

3Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
et al. 2007) The notion of dialectical proﬁles interestingly enough appears
to be closely linked to what we present in this paper if we regard a dialectical proﬁle or route within the discussion as an instantiation of the possible
moves outlined in a critical discussion dialogue protocol and the ﬂow-chartin which our present example has been presented (see Figure 5.) A continuation of the study should take note of these facets of the pragma-dialecticaltheory and reﬁne the crude correspondences arrived at in what follows. We
will ﬁrst introduce the most relevant aspects of the pragma-dialectical theory and of the AIF in paragraphs 2 and 3. Then we will present a preliminary
correspondence between the two in paragraph 4. Paragraph 5 will conclude
this paper with an outline of our endeavours so far and of the opportunities
it opens up for future research.

2. The pragma-dialectical approach to argumentation
2.1. The ideal model of a critical discussion
In the pragma-dialectical approach argumentative discourse is analysed relative to the ideal model of a critical discussion. This fully developed
discussion model is: normative, as opposed to an empirically distinguisheddialogue type; takes into account all stages of a discussion instead of merely the inference-drawing stage; and pertains primarily to natural language
discourse in contrast to just arguments expressed in an artiﬁcial language
devoid of a normative basis for their relation to actual discourse.
According to the pragma-dialectical ideal of reasonableness a critical
discussion is aimed at resolving the diﬀerence of opinion based on the merits of the respective points of view. In the discussion the parties take on theroles of protagonist and antagonist, respectively arguing for the standpoint
or criticising its tenability. Thus they engage in a social interaction aimed
at achieving mutual agreement about the (un)acceptability of the proposition expressed in the standpoint.3 To this avail the discussants performspeech acts and pass through the four stages of a discussion all systematically fulﬁlling a necessary function in the process of reasonably resolving
the diﬀerence of opinion. The discussants start oﬀ from a set of externalised material and procedural points of agreement, indicating what common
ground there is. The dialectical rules ensure a methodical resolution-oriented
3 Internal deliberation or monologue on this take would be reconstructed as a dialectical process in which both discussion parties are fulfilled by the same individual anticipatingon counter moves.

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Correspondence between the Pragma-Dialectical Discussion Model and...
discussion procedure based on these conceded premises – ex concessis – byprescribing dialectical obligations and rights to the discussants. The sections
that follow will explain the stages (2.2), the speech act distribution (2.3)
and the 15 rules (2.4) of a critical discussion.
2.2. The stages of a critical discussion
Discussion parties can only resolve their diﬀerence of opinion ina reasonable manner if they go about in a well-regimented and systematic manner. In the confrontation stage the parties recognise their diﬀerenceof opinion and externalise it. In a single, non-mixed diﬀerence of opinion
one of the parties will have committed himself to one particular standpoint
which the other party disagrees with. This disagreement is expressed bycasting doubt on the standpoint. The disagreeing party can also not merely doubt the standpoint but actually hold an opposite point of view. This
would result in a mixed diﬀerence of opinion where both discussants havethe obligation to defend their own standpoint if they are prompted to do so.
There can also be disagreement about several separate but related standpoints at the same time. In such case the diﬀerence of opinion becomes
multiple. For the remainder of this paper we will focus on single, non-mixed
diﬀerences of opinion as the elementary case from which more elaborate
and complex forms could be composed. The discussion parties will in the
opening stage agree on a set of mutually accepted premises and procedures,and commit themselves to engage in a critical discussion. At this time theyalso distribute the roles they will each play in the next stage of the discussion. One of the parties will defend the standpoint at issue as protagonist
by putting forward argumentation in support of it.4 The other party will
cast doubt on the standpoint and, as antagonist, will critically challenge theargumentation.5
Once these mutual commitments have been made, the argumentation
stage commences. In this stage the protagonist tries to defend the standpointby arguing for it, i.e. by performing the complex speech act of argumentation in defence of his standpoint. The antagonist in turn can ask for further
4 In most instances it will be the advancer of the standpoint who takes on the role ofprotagonist and the doubter who takes on the role of antagonist, but the parties are free
to decide otherwise as would suit their particular situation.
5 In the sections involving the pragma-dialectical theory the term “argumentation”
will be used in a rather specific, technical sense in line with Pragma-Dialectical literature and with its natural meaning in most Roman and Germanic languages. It is taken
to denote the constellation of arguments advanced in support of (and not including)a standpoint. It also is the term that names the complex speech act covering the assertives performed in discourse in support of the standpoint expressed.

5Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
clariﬁcation, question the acceptability or justiﬁcatory force of the argumentation – as such soliciting further defence by the protagonist – or hecan accept (part of) the protagonist’s argumentation. Finally the discussion
will enter the concluding stage where the current diﬀerence of opinion gets
resolved by either a retraction of the initial standpoint due to the protagonist’s inability to conclusively defend it, or the mutual acceptance of thestandpoint due to a defence that was conclusive. Of course if the protagonist has to retract his standpoint this does not mean that the contradictionof the propositional content of it has been constructively argued for.6 Suchwould take another critical discussion.
2.3. The distribution of speech acts in a critical discussion
The discussants go through the stages of the discussion by performing
speech acts. The model of a critical discussion speciﬁes which types of speechacts have to or may be performed by each party at each stage. In analysis,
the speech acts that are geared towards the resolution of the diﬀerence of
opinion constitute the argumentatively relevant utterances that need to bereconstructed. (van Eemeren et al. 1993) Assertives are performed to express
the initial standpoint and to compose the complex speech act of argumentation in defence of the standpoint. Such a complex speech act is made upof the individual assertions and is at a textual level intrinsically connectedto the assertion by which the contested standpoint is advanced. Throughcommissives the parties accept standpoints and argumentation, and agree
on mutual commitments towards common starting points, procedures or
the outcome of intersubjective procedures and (sub-)discussions. Directives
are used to prompt the other party to defend his standpoint and argue forit. Discussants can always ask for clariﬁcation by performing a directive orprovide clariﬁcation themselves with a usage declarative.7
2.4. The procedural rules of a critical discussion
The discussion moves discussants may make through performing speechacts while going through the stages of a critical discussion are regimented
by 15 rules that ensure a reasonable dialectical procedure. These rules areproblem-valid in that obeying them is a necessary condition for reaching theintended outcome of critically testing the standpoint at issue and resolving
6

Testifying to the critical rationalist principles of the theory.
The tables in (van Eemeren et al. 2007, p. 16) and (van Eemeren and Grootendorst
1984, p. 105) show the speech acts relevant for critical discussion and their distribution
over the discussion stages and between the discussion parties.
7

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Correspondence between the Pragma-Dialectical Discussion Model and...
the diﬀerence of opinion in a reasonable manner. Any violation of the rules
for a critical discussion results in a frustration of the resolution procedureand can therefore be called fallacious.8 We will quickly go through the rules and will reproduce some from (van Eemeren and Grootendorst 2004)
if they are of particular interest to our current project.9 The ﬁrst of the
15 rules speciﬁes the unconditional right of discussants to advance or cast
doubt on any standpoint regarding any proposition regardless of topic or(speaker’s) status. The second rule allows the discussant doubting a standpoint to prompt the discussant who advanced the standpoint to actually
defend it. Advancing a standpoint in principle commits the discussant to
defend it if he is challenged; the burden of proof rests with he who advances
a standpoint. There is no such commitment to challenging the standpoint
on behalf of the discussant who casted doubt. One provision here is the principle of non bis in idem: the proponent of a standpoint is never obligatedto defend a particular standpoint if it has already been successfully defended before under the same discussion rules, and premises, against the same
opponent. Furthermore a discussion cannot proceed without the discussion
parties ﬁrst agreeing on certain basic rules and premises.
RULE 3:The discussant who is challenged by the other discussant to defend thestandpoint that he has put forward in the confrontation stage is always obligated to accept this challenge, unless the other discussant is not preparedto accept certain shared premises and discussion rules; the discussant remains obligated to defend the standpoint as long as he does not retract it
and as long as he has not successfully defended it against this particular
discussant on the basis of the particular agreed premises and discussion
rules.

During the discussion the parties play the roles of protagonist, defending
the standpoint, and antagonist, criticising it. That the discussants need tocommit themselves to these roles for the remainder of the current critical
discussion is laid out in rule 4. After deciding on the discussion rules, discussants should not digress from them or call them into question again during
the current discussion. If a discussant wants to discuss the status of one of
8 For more on fallacies as violations of the rules of a critical discussion, see (vanEemeren and Grootendorst 1992) and (van Eemeren et al. 2002).
9 The rules as presented here are very similar to those in (van Eemeren and Grootendorst 2004) but are revised slightly in some occasions. Of course the rules of a critical
discussion still apply equally to male and female discussants, but in the interest of brevity
we use male pronouns to refer to both protagonists and antagonists.

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Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
the agreed upon rules this happens outside of the current discussion, giving
rise to a meta-discussion.10
RULE 5:The discussants who will fulfil the roles of protagonist and antagonist in
the argumentation stage agree before the start of the argumentation stage
on the rules for the following: how the protagonist is to defend the initialstandpoint and how the antagonist is to attack this standpoint, and in whichcase the protagonist has successfully defended the standpoint and in whichcase the antagonist has successfully attacked it; the rules in which this islaid down apply throughout the duration of the discussion, and may not becalled into question during the discussion itself by either of the parties.

In the argumentation stage discussants can perform three types of speech acts to critically asses the tenability of the standpoint. First of all theprotagonist can perform the complex speech act of argumentation througha constellation of assertives according to rule 6a. This defence of the standpoint is provisional until the antagonist performs a commissive conﬁrming
the acceptability of the argumentation. If the antagonist does not accept
the argumentation he will perform the illocutionary negation of the commissive and a directive to request new argumentation on the basis of theunacceptability of the propositional content or of the justiﬁcatory force of
the argumentation to the standpoint (rule 6b).
In case the argumentation is attacked on its propositional content, rule 7
states that the protagonist and antagonist will employ the intersubjective
identification procedure by checking whether the proposition is part of theset of material starting points which were mutually agreed on in the openingstage. If they agree it is not part of the starting points they can either use
a method they speciﬁed in the procedural starting points to check the acceptability of the proposition – for example looking it up in an encyclopedia– or they can engage in a sub-discussion with the contested proposition as
sub-standpoint.
If the argumentation is attacked on its justiﬁcatory (or refutatory) force,rule 8 determines that in the case that the reasoning in the argumentation
is fully externalised and is dependent on logical validity, the discussants can
proof the validity through the intersubjective inference procedure making

10 Which should not be confused with a sub-discussion. We will encounter the latterin the argumentation stage, while the meta-discussion (also called meta-dialogue by someauthors) is used to determine the common commitments of the discussants in the openingstage.

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Correspondence between the Pragma-Dialectical Discussion Model and...
use of the system of logic agreed upon as procedural starting point in the
opening stage. Should the argumentation not be dependent on logical validity or fail to be fully externalised it is not logically valid and will makeuse of an argument scheme. Ordinarily such an argument scheme will not
be explicitly stated and will need to be reconstructed. This reconstruction
will be carried out by following the intersubjective explicitisation procedure
which will determine the particular argument scheme employed. Once thishas been done, the discussants will have to decide whether the scheme isadmissible and has been applied properly. They do this by using the intersubjective testing procedure. The admissibility is tested by checking whether
this argument scheme and its accompanying critical questions are part ofthe procedural starting points agreed upon in the opening stage. The application of the scheme is tested by posing the critical questions associatedwith it and judging whether it can withstand such challenges.
RULE 8:11
a. The protagonist has successfully defended a complex speech act of argumentation against an attack by the antagonist with regard to its justificatory (orrefutatory) force if the application of the intersubjective inference procedureor (after application of the intersubjective explicitisation procedure) of theintersubjective testing procedure, yields a positive result;b. the antagonist has successfully attacked the justificatory (or refutatory)
force of a complex speech act of argumentation if the application of theintersubjective inference procedure or (after application of the intersubjective explicitisation procedure) of the intersubjective testing procedure yields
a negative result.

Rule 9 pertains to the conditions of the conclusive attack or defence ofa standpoint. The standpoint has been defended conclusively if the antagonist did not manage to successfully attack the propositional content or thejustiﬁcatory (or refutatory) force of the argumentation in support of thisstandpoint. The standpoint has been conclusively attacked if the antagonist did manage to successfully attack the content or force of every complex
speech acts of argumentation performed by the protagonist in support ofthis standpoint.

11 By having a disjunctive form in part b. this rule forces the choice we make laterin our dialogue protocol when it comes to not regarding argumentation which failed theintersubjective inference procedure as salvageable by employing the intersubjective explicitisation procedure first and then subsequently checking its tenability through the testingprocedure.

9Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
Although the aim of the critical discussion is to critically test the tenability of a standpoint, the antagonist is under no obligation to attack theargumentation in support of a standpoint in all possible ways. The criticalstance of the antagonist can be short-lived if he feels compelled to accept
the ﬁrst attempt the protagonist makes at defending the standpoint. The
antagonist does retain the right to critically challenge the argumentation
throughout the discussion though as long as he is not repeating himself
after a successful defence or an act of retraction with regards to the standpoint or argumentation for it by the protagonist.
Because the protagonist should defend the standpoint, he has to support
it by means of advancing argumentation. Quite similar to the antagonist’s
right expressed in rule 10, the protagonist retains the right to defend hisargumentation throughout the discussion. Should an argumentation be attacked on both its propositional content and its justiﬁcatory force, thenthe protagonist has to defend against both. Aside from the right to defend
a proposed argumentation against attacks, rule 12 allows the protagonist to
retract the commitment to an argumentation he advanced earlier in orderto support the standpoint in a diﬀerent way.
The rules so far allow for the discussants to frustrate the resolution of
their diﬀerence of opinion by allowing them to repeat performing the same
speech acts over and over again. The orderly conduct of a critical discussion is regulated through rule 13 by posing a restriction on the repetition
and mixing of speech act performances and by having the discussants takealternating turns.
In order to end the particular instance of a critical discussion, rule 14
states the pre-conditions for the speech acts discussants may perform in the
concluding stage of the discussion. The discussants will decide on the outcome of the discussion leading the protagonist to have to retract his standpoint if it has not been conclusively argued for or leading to the antagonist
having to retract his doubt regarding the standpoint if it has. Although
rule 14 allows for an outcome of the discussion in which none of the discussants has to change their commitment to the standpoint, such a termination
can not be regarded an instance of a reasonably resolved diﬀerence of opinion.
Because of the nature of the dialectical procedure (i.e. being based on
externalised commitments) it is very important that the discussion parties
optimally formulate and interpret their utterances. The utterances should
further the resolution process, not obstruct it. To this end, discussants may
always perform a usage declarative themselves or ask their dialectical opponent to do so, in which case the other is obligated to comply.
10Correspondence between the Pragma-Dialectical Discussion Model and...
This concludes the normative 15 rules of a critical discussion as well as
our present introduction of the pragma-dialectical theory. In paragraph 4
we will establish some basic correspondences between the pragma-dialecticaltheory we have just seen and the Argument Interchange Format which will
be introduced in paragraph 3.
3. The Argument Interchange Format
Argumentation theory is a large and diverse ﬁeld stretching from analytical philosophy to communication theory and social psychology. The computational investigation of the space has multiplied that spectrum by a diversity of its own in semantics, logics and inferential systems. One of the
problems associated with the diversity and productivity of the ﬁeld, however, is fragmentation: with many researchers from various backgrounds
focusing on diﬀerent aspects of argumentation, it is increasingly diﬃcult toreintegrate results into a coherent whole. This in turn makes it diﬃcult for
new research to build upon old. To tackle this problem, the computational argument community has initiated an eﬀort aimed at building a common ontology for argument which will support interchange between diﬀerent
research projects and applications in the area: the Argument Interchange
Format (AIF).
Owing to its roots in computational argumentation, a main aspirationof the AIF is to facilitate data interchange among various tools and methods
for argument analysis, manipulation and visualization.12 Whilst the ideal ofa single format might not be feasible in such a diverse ﬁeld, a common
consensus on the standards and technologies employed is desirable. Furthermore, the AIF project aims to develop a commonly agreed-upon core
ontology that speciﬁes the basic concepts used to express argumentative
information and relations. The purpose of this ontology is not to replace
other languages for expressing argument but rather to serve as an abstract
interlingua that acts as the centrepiece to multiple individual languages forargumentation. These argument languages can be, for example, logical languages (e.g. ASPIC’s defeasible logic, see Prakken 2010), visual languages(e.g. Araucaria’s AML format for diagrams, see Reed and Rowe 2004) or
natural language (e.g. as used in the pragma-dialectical approach, see van
Eemeren and Grootendorst 2004).
12 Even though the AIF has a clear computational objective, such tools and methods
need not necessarily be implemented as computer programs: a pragma-dialectical analysis,for instance, is a method that is not implemented as a program.

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Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
A common abstract ontology for argumentation is interesting froma practical perspective because it drastically reduces the number of translation functions that are needed for the diﬀerent argumentation languages
to engage with each other; only translation functions to the core AIF ontology have to be deﬁned (i.e., n instead of n2 functions for n argumentation languages). In this way, data interchange is facilitated and methods
that use diﬀerent languages can be applied to the same argument resources
expressed in the AIF. With the AIF as an interlingua we can, for example, use a diagramming tool such as Araucaria to visualise arguments thatwere interpreted from a natural language text using pragma-dialectical methods. From a more theoretical perspective a common ontology is interesting
because it provides a conceptual anchoring point for the various diﬀerent
argumentation languages.
3.1. The AIF ontology
The AIF is constructed as an ‘ontology’, which in the context of computer science, and knowledge representation in particular, is a way of deﬁning
the key concepts of a domain and the relationships between them. In the
AIF ontology, arguments and their mutual relations are described by conceiving of them as an argument graph. The ontology falls into two natural
halves: the Upper Ontology and the Forms Ontology. The Upper Ontology,
introduced in (Chesñevar et al. 2007), describes the graphical language ofdiﬀerent types of nodes and edges with which argument graphs can be built(i.e. the “syntax” for the abstract language of the AIF ontology). The Forms
Ontology, introduced by (Rahwan et al. 2007), allows for the conceptual deﬁnition of the elements of the graphs, that is, it describes the argumentative
concepts instantiated by the elements in a graph (i.e. the “semantics” forour abstract language).
The Upper Ontology places at its core a distinction between information, such as propositions and sentences, and schemes, general patterns ofreasoning such as inference or conﬂict, which are used to relate pieces of
information to each other. Accordingly, there are two types of nodes forbuilding argument graphs, information nodes (I-nodes) and scheme nodes(S-nodes) and I-nodes can only be connected to other I-nodes via S-nodes.
That is, there must be a scheme that expresses the rationale behind therelation between I-nodes. In the basic AIF ontology, scheme nodes can berule application nodes (RA-nodes), which denote speciﬁc inference relations,conﬂict application nodes (CA-nodes), which denote speciﬁc conﬂict relations, and preference application nodes (PA-nodes), which denote speciﬁc
preference relations.
12Correspondence between the Pragma-Dialectical Discussion Model and...
The Forms Ontology is important in that it contains the argumentative
concepts instantiated by the graph. The Forms Ontology is essentially basedon schemes, general patterns of reasoning, that is, inference schemes, conﬂict schemes or preference schemes. Informally, inference schemes are rulesof inference, conﬂict schemes are criteria (declarative speciﬁcations) deﬁning conﬂict (which may be logical or non-logical) and preference schemes
express (possibly abstract) criteria of preference. These main scheme types
can be further classiﬁed. For example, inference schemes can be deductive or
defeasible. Defeasible inference schemes can be further subdivided into more
speciﬁc argumentation schemes, such as the schemes for Causal Argument
or for Argument from Sign in (Walton et al. 2008) or the pragma-dialecticalargument schemes based on analogy, sign or cause (see van Eemeren and
Grootendorst 1992).13 There are various ways to represent the schemes in
the Forms Ontology. Rahwan et al. (2007), for example, deﬁne them asgraphs of so-called form-nodes (F-nodes) whilst Rahwan et al. (2010) deﬁneschemes as combinations of classes of statements in Description Logic. In
this paper, we will represent individual schemes as a list of features, viz.
Scheme name Analogy

Modus Ponens

Scheme typedefeasible inference scheme

deductive inference scheme

Premises

A is true (false) for C1
C1 is similar to C2Conclusion

A is true (false) for C2

ϕ
ϕ⇒ψ
ψ

Presumption

The similarity between C1 and C2
is relevant to the comparison

Exception

A is false (true) for another C3 similar to C1 none

none

Table 1: Two possible inference schemes in the Forms Ontology

Note that the critical questions for a scheme are implicitly modelled;some of them point to an implicit presumption (‘Is the similarity suﬃciently
relevant?’), others correspond to the exception (‘Is there some other C3 thatis also similar to C1, but in which A is false?’) or they may ask after one ofthe premises (‘Is A true for C1?’).
The Forms Ontology and the Upper Ontology are intimately connected because speciﬁc applications of schemes (denoted by RA-, CA- and

13 It is important to note that the AIF ontology does not (and should not) legislate
as to which schemes or forms are the correct ones; different schemes are each plausible
according to particular theoretical assumptions.

13Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
PA-nodes) are instantiations of general (inference-, conﬂict- and preference-)
schemes; in other words, the S-nodes fulfil the schemes expressed in theForms Ontology. As an example of argument graphs that fulﬁl schemes consider Figure 1, in which two arguments for Plato’s (p) mortality are given,
one based on Socrates’ (s) mortality and the fact that Plato and Socrates
are similar (e.g. they are both men) and another based on the fact that
Plato is a man (and therefore mortal). Rectangular nodes are I-nodes andellipses are S-nodes; the concepts from the Forms Ontology that are fulﬁlled
by the nodes (see the two schemes for Analogy and Modus Ponens above)
are rendered next to the nodes.

Figure 1. Argument graphs in the language of the AIF ontology

3.2. Dialogue in the AIF
The basic AIF ontology, as described in (Chesñevar et al. 2007; Rahwan
et al. 2007), does not include ways of representing argument2, that is, dialogical argument.14 One reason for this is that as Prakken (2005) remarks,
while there are a number of well-deﬁned systems for dialogue games, formany of these systems the underlying design principles are mostly implicit.
Despite this, Reed et al. (2008; 2010) have recently made some tentative
steps in the way of including dialogical argument2 in the AIF ontology. The
extended ontology, dubbed AIF+, extends the base ontology to support representation of dialogue protocols (i.e. speciﬁcations of how dialogues are toproceed), to support representation of dialogue histories (i.e. records of how
given dialogues did proceed) and to support representation of the connection between dialogic argument2 and argument1. One underlying premise ofthis work is that any extensions to the basic AIF should include a minimal
amount of extra representational machinery. Below, we brieﬂy summarize
the work on the AIF+ ontology.
14 Here, we refer to O’Keefe’s (1977) two characterizations of the term “argument”:
argument1 and argument2. Argument1 refers to an argument as a static object (thepragma-dialectical notion of argumentation) and is described by sentences such as “heprepared an argument”. Argument2 refers to a dialogue (the pragma-dialectical notion ofcritical discussion) and is described by sentences such as “they had an argument”.

14

Correspondence between the Pragma-Dialectical Discussion Model and...
In the context of the AIF+ ontology, it is proposed that locutions aremodelled as a subclass of I-nodes called L-nodes. This approach is followed
primarily because statements about locution events are propositions that
could be used in arguments. So for example, the proposition Plato says,‘Socrates is mortal’ could be referring to something that happened in a dialogue (and later we shall see how we might therefore wish to reason about
its propositional content, Socrates is mortal) but it might also play a role ina structure of the form argument1 (say, as a premise in an argument fromexpert opinion or of an argument about Plato’s communicative abilities).
A dialogue is more than a mere sequence of unconnected locutions:
there is a functional relationship between diﬀerent locutions, especially if we
consider them in a dialogue with set rules. Imagine, for example, a dialogue
in which Plato says, ‘Socrates is mortal’ and Aristophanes responds byasking, ’Why is that so?’ In trying to understand what has happened, one
could ask, ‘Why did Aristophanes ask his question?’ Now, there is at least
one answer we could give purely as a result of the dialogue protocol, namely,‘Because Plato had made a statement’. That is to say, there is a functional
relationship between the proposition, Plato says, ‘Socrates is mortal’ andthe proposition, Aristophanes asks why it is that Socrates is mortal. That
relationship can be seen as a scheme, a pattern of reasoning (but perhaps
not as a conventional inferential scheme as for RA-nodes) of which thegrounds lie in the deﬁnition of the dialogue game. Thus, by analogy to the
ontological machinery of schemes, we can view transitions as Forms thatare fulﬁlled by an S-node for transitions between locutions, which we calltransition application nodes (TA-nodes).
Many protocols for dialogue games associate constraints with what are
here called transitions. A transition scheme can thus be interpreted as having a presumption in much the same way that speciﬁc inference schemes
have presumptions (cf. the scheme for argument from analogy in Table 1).
These transitions and the conditions on them, are not all there is to a protocol: some locutions have conditions which do not directly refer to anotherlocution in the dialogue, that is, constraints on individual locutions. We
specify these constraints as pre- and post-conditions on operators that correspond to locutions. Figure 2 shows the ontological structure of locutions
and transitions.
For examples of locutions and transition schemes, consider Table 2
and 3, which show the Challenge and Resolve locutions and the ChallengeResolve transition from Mackenzie’s (1979) DC protocol. Notice the difference between constraints-as-presumptions and constraints-as-preconditions: the precondition for a Challenge always holds, no matter to which
15Jacky Visser, Floris Bex, Chris Reed and Bart Garssen

Figure 2: Transition schemes and locutions

other locution the Challenge responds. The presumptions on a ChallengeResolve transition, however, only hold when a Resolve is oﬀered as a response to a Challenge.
Locution name

Challenge

Resolve

FormatWhy P?

Resolve whether P

Precondition description

P is not in speaker’s commitment

none

Postcondition description

P is in hearer’s commitment
Why P? is in speaker’s commitment

none

Table 2: Two locutions from Mackenzie’s DC protocol

Scheme name

Challenge – Resolve

Start Locution Description

Why P?

End Locution Description

Resolve whether ‘if Q then P’

Presumption Description

P is an immediate consequence of Q
Q is a conjunction of statements to all of which the hearer
is committed

Table 3: A transition in Mackenzie’s DC protocol

One interesting question is how exactly L-nodes are connected to
I-nodes in argument1. So, for example, what is the relationship between
the proposition Socrates is mortal and the proposition Plato says, ‘Socrates is mortal’? The answer to the question is already available in the workof Searle (1969) and later with Vanderveken (1985): the type of the link
between a locution and its propositional content is dependent on the typeof illocutionary force which the performer of the speech act assumes. In
the AIF+ ontology, the relation between a locution and its propositional
content is hence captured by illocutionary schemes. Speciﬁc applicationsof these schemes are then, following the now familiar pattern, represented as YA-nodes, which describe passage between L-nodes (“elements” ofargument2) and I-nodes (“elements” of argument1). For example, Plato says,
16

Correspondence between the Pragma-Dialectical Discussion Model and...
‘Socrates is mortal’ is linked to Socrates is mortal by a YA-node which isan instance of the “asserting” illucutionary scheme.
A link between and L-node and an I-node is warranted by the constitutive rules for the speech act that is performed. In natural contexts, the mostimportant types of constitutive rules are the preparatory and sincerity rules,
for which unfulﬁllment results in defectiveness of a speech act (Searle andVanderveken 1985). AIF naturally supports diﬀerent conceptions of speechacts and of illocutionary force in that it allows for multiple sets of illocutionary schemes (just as it allows for multiple sets of argumentation schemes).
As a result, it can represent van Eemeren and Grootendorst’s (1984) modiﬁcations to Searle’s and later, Searle and Venderveken’s rules and conditions
on speech acts. For example, an assertion may be successful but still defective, if its performer declared what in fact he disbelieves: a locutor may
not satisfy constitutive rules and still have a chance to perform a successful
speech act, since a receiver may not notice their unfulﬁllment. Thus, thesuccessful adherence to constitutive rules can be viewed as presumptions on
the applications of illucutionary schemes and all of the existing AIF machinery handles the representation on attacks on the successful application of
illocutionary force.
3.3. Calculated properties in the AIF
The language of the AIF+ ontology allows us to “record” argumentsof both type 1 and 2 and the links between them. However, arguments
based on, for instance, counting, weighing, comparing or evaluating otherarguments all involve processes (counting, weighing, comparing, evaluating)that cannot be captured in the AIF itself (and nor should they be, for otherwise the AIF would swell to some general purpose programming language).
These various processes might collectively be thought of as ways of calculating properties about the arguments that the AIF+ ontology represents.
It is not that such arguments cannot be represented at all. But rather, if
arguments are based on these calculated properties – arguments such as“the prosecution has not provided suﬃcient evidence for a conviction, so
the accused is released” – then they can only be represented in the same
way as normal propositions, i.e., as I-nodes. The language of the AIF+
ontology has no way of capturing the link between such a statement and,say, the existence or non-existence of a set of other nodes. For argument1
structures this is a relatively small problem, but excludes, as the previous
example demonstrates, some relatively common forms of legal argument.
But for dialogue, the matter is more serious. Protocol rules are very often
deﬁned on the basis of calculated properties of dialogue histories: the exi17

Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
stence or non-existence of particular claims, the current status of claims andcommitments.

4. Critical discussion in the AIF
Having introduced the pragma-dialectical model of a critical discussion
in paragraph 2 and the AIF in paragraph 3, we turn our attention to thecorrespondence between the two in paragraph 4. We will begin by relating
the core concepts of the pragma-dialectical model to the building blocks of
the AIF ontology. After which we will tentatively re-introduce the model ofa critical discussion in terms of a dialogue protocol by means of a ﬂow-chartthat visualises the moves discussants can make within a discussion gameand we will highlight some of the most noteworthy and interesting locution
pairs found within the protocol.
4.1. Pragma-dialectical notions in AIF terms
Evaluating argumentative discourse in accordance with the standard
pragma-dialectical model of a critical discussion requires the constructing ofan analytic overview. (van Eemeren and Grootendorst 2004, pp. 118–122)
This overview covers all analytically relevant, argumentative elements ofthe discourse. Sections 4.1.1 to 4.1.6 correlate these core elements ofpragma-dialectical analysis to the core ontology of the AIF.
4.1.1. Standpoints

In pragma-dialectical theory, a standpoint is a combination of a proposition and an attitude towards that proposition. Clearly, the propositional content of a standpoint corresponds very closely to an I-node in
the AIF, but I-nodes (necessarily) omit agent-relativised attitudes towards
their content, so an I-node capturing some proposition p cannot directly
correspond to a standpoint such as +/p. Houtlosser (1994) elucidates thepragma-dialectical foundation that suggests a central role for speech acts,
and intimates that oﬀering a standpoint is a distinct speech act, albeit one
that may be performed simultaneously with others. We might call the illocutionary force that accompanies such a speech act (rather cumbersomely),‘standpointing’. Armed with this type of illocutionary force, we have a further point of correspondence: a propositional report of a discourse event
such as Bob says p is the case is captured by an L-node; its propositional
content, p, is captured by an I-node, and the connection between them iscaptured by a YA scheme instantiating an illocutionary scheme for stand18

Correspondence between the Pragma-Dialectical Discussion Model and...
pointing. Bearing in mind that the AIF can directly represent the underlying‘Sentence-level’ assertion that also connects the L and I nodes, the picture
is as in Figure 3, below.

Figure 3. Standpointing as illocutionary force

Whilst Figure 3 represents a reasonable AIF interpretation of the speech
act constitution of standpoints, it fails to provide us with the locus ofa standpoint – although we have a representation of standpointing, we do
not yet have one for a standpoint. Two observations lead to a solution. The
ﬁrst observation is that van Eemeren and Grootendort (1984) provide a propositional interpretation of a standpoint, viz. (in our example): Bob’s pointof view in respect of the expressed opinion p is that this expressed opinion p
is (not) the case (1984: 114). The second is that this proposition can be
deduced from an AIF graph in which there is a sentence level assertion anda higher textual level speech act of standpointing between a single L node
and a single I node. In other words, the standpoint can indeed be represented as an I node (it is, after all, a proposition like any other), but one which
is a calculated property.
This characterisation of the speech-act nature of standpoints does havesome limitations. For van Eemeren and Grootendorst, the relationship between the speech act of standpointing and the speech act of asserting is oneof supervention, that is, the content of the standpointing act is precisely
the asserting act. The AIF, however, enforces strict type limitations, and isfounded upon the early speech act model in which all speech acts (if they
have any substantive content at all) have propositional content. As speechacts themselves are not propositions, for the AIF, the passage of illocutionary force captured by the illocutionary scheme cannot itself be the subjectof illocutionary force. In this way the current ontology of the AIF prohibits direct connection from one illocutionary scheme to another. Exploring
this restriction further in response to the pragma-dialectical approach is aninteresting avenue for further investigation.
19

Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
On the other hand the analysis also has some strengths. The AIF interpretation can cope with Houtlosser’s reconstruction of arbitrary speechacts (not just assertives) between the propositional report of the discourse
event and the propositional content (i.e. the content of the standpoint), andcan similarly handle multiple such speech acts if, for example, both a directive and a (reconstructed) assertive are identiﬁable at the sentence level.
The AIF interpretation also preserves a clear distinction between a standpoint and other speech acts, which is important for subsequent dialogicalmechanics (see Section 4.3). And ﬁnally, it is possible to expand the analysis presented in Figure 3 explicitly to capture Houtlosser’s (1994) more
reﬁned account of the complex speech act of standpointing in which it is
the acceptability of the sentence level assertive which is the target of the
speech act. Illocutionary schemes capture presumptions and constitutive
requirements on speech acts in the same way that argumentation schemes
capture presumptions and constitutive requirements on inferences. In addition to Searle-like conditions and consitutive rules, the illocutionary scheme
for asserting might also typically capture the implicit presumption of acceptability generated by the Interaction Principle. These implicit components
act as potential growth points for argument and can be made explicit whenappropriate. We could thus revise the picture as in Figure 4, which makes
explicit the proposition corresponding to the presumption of acceptability,
and then renders that presumption the target of the illocutionary force ofstandpointing.

Figure 4. Standpointing with acceptability of sentence level assertion

Figure 4 is a signiﬁcantly more complex interpretation, so for the sake ofclarity in what follows, we retain the analysis in Figure 3, because nothingis lost in our investigation if we do so.
4.1.2. Discussion roles

The distribution of the discussion roles is externalised in the openingstage. The discussion parties mutually commit to the distribution for the20

Correspondence between the Pragma-Dialectical Discussion Model and...
remainder of the discussion. From then on, every L-node is marked witha speciﬁc agent property corresponding to a unique name for an interlocutor, and the mapping between these unique names and their roles in thisparticular dialogue is handled by the commitments established during the
opening stage. Thus, for example, we might imagine a move m in a dialogue which requires the protagonist to have earlier said x. We may havea representation of the utterance of x for which the agent property is Bob,and furthermore, we may have the parties having committed that for this
dialogue Bob is protagonist. The precondition on the move m would thus
express that there exists some agent about whom there exists a commitmentof taking on the role of protagonist, and that this agent must be the valueof the agent property of an L-node earlier in this same dialogue.
4.1.3. Starting points

The starting points of an argument are the conceded propositions mutually agreed upon as a part of the common ground, as checked in theintersubjective identiﬁcation procedure. For the AIF, starting points are represented as I-nodes (starting points in pragma-dialectical theory do notinclude derivations or applications of inferences, or instances of conﬂict
relations, and so do not include complexes of I-nodes and S-nodes). In
pragma-dialectical theory, starting points may also include rules of inference, which correspond to components of the Forms ontology (referred
to as F-nodes in (Rahwan et al. 2007)). Direct reference to F-nodes fromwithin instances of AIF graphs is not currently possible: it is not possible to argue about or agree to or talk about general rules of inference,as it is in some other systems – particularly those with a legal heritage
where the evolution of legal rules is of central importance. This is a known
limitation of the AIF which is under investigation elsewhere. Here we limit ourselves to handling propositional starting points. Clearly the propositions that are the subject of the starting points are I-nodes. However, the fact that they are starting points needs to be handled explicitly
too. As with much of pragma-dialectical theory, the establishment of starting points has a dialogical basis. As such, the fact that a given proposition is a starting point in a given dialogue is a commitment – that is, an
I-node corresponding to a property calculated on the basis of a (set of)
L-node(s). So for example, the two L nodes, Bob said that he thought theyboth agreed on p, and Wilma said that she agreed, might be used to calculate
the property that p is a starting point, which itself would be represented
as an I-node.

21Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
4.1.4. Argumentation

The concept of ‘an argumentation’ in pragma-dialectical theory corresponds fairly closely to O’Keefe’s (1977) characterisation of argument1. As
a result, an argumentation is simply any connected subgraph of an AIF
graph which does not include applications of transitional (TA) or illocutionary (YA) schemes. To include TAs or YAs would be to include dialogue as such, so they must be excluded. Notice however that the deﬁnition
does allow L-nodes. This is because L-nodes can be used to play a role inarguments1. For example, one might use the premise, Bob said bananas areyellow as a basis for an inference to the conclusion that Bob can speak,or Bob knows English, or Bob has seen a banana, and so on. In fact, onerather common use of L-nodes in this way is in arguments from authority(and related forms) – so we must not prohibit L-nodes from appearing inargumentation.
4.1.5. Argumentation structures

The pragma-dialectical model recognizes several distinct structures ofargumentation, each of which corresponds directly to particular arrangements or constraints on AIF graphs:• Single argumentation corresponds to a subgraph of AIF involving
exactly three nodes: an I-node corresponding to some proposition p,
an I-node corresponding to some proposition q, and an RA-node connecting q to p, with the further constraint that there are no other incoming RA-nodes to p (in fact this last constraint is rather more diﬃcult
to determine since it is relativised to the current dialogue – clearly there
might be many other arguments for p, but their existence is of no import
if they are not adduced in the dialogue at hand).
• Multiple argumentation corresponds to a subgraph of AIF involving atleast ﬁve nodes: an I-node corresponding to some proposition p, two further I-nodes corresponding to propositions q and r, and two RA-nodes,
one connnecting q to p, the other connecting r to p. There may be
any number of other RA- and I-nodes in the subgraph in addition: thestructure described is suﬃcient for the subgraph to count (at least) as
multiple argumentation structure.
• Coordinative argumentation corresponds to a subgraph of AIF involving
at least four nodes: an I-node corresponding to some proposition p, twofurther I-nodes corresponding to propositions q and r, and an RA-node
which connects q and r to p. There may be any number of other RAand I-nodes in the subgraph in addition: the structure described is suﬃcient for the subgraph to count (at least) as coordinative argumentation
structure.
22

Correspondence between the Pragma-Dialectical Discussion Model and...
• Subordinative argumentation corresponds to a subgraph of AIF involving at least ﬁve nodes: three I-nodes corresponding to propositions p,
q and r, and two RA-nodes, the ﬁrst connecting q to p, and the second
connecting r to q. There may be any number of other RA- and I-nodes
in the subgraph in addition: the structure described is suﬃcient for the
subgraph to count (at least) as subordinative argumentation structure.
4.1.6. Argument schemes and critical questions

Argument schemes in pragma-dialectical theory have a direct counterpart in the AIF’s representation of rules of inference. The schemes themselves a characterised abstractly (that is to say, uninstantiated) in the Forms
ontology, and are then instantiated by RA schemes in speciﬁc examples. For
the AIF it is important to distinguish the form of, say, Argument from Authority (which deﬁnes the form that its premises and conclusion take; deﬁnes its presumptions and exceptions; and deﬁnes its critical questions), froma given instance of Argument from Authority (which has speciﬁc premises,
conclusions and possibly some of the implicit presumptions and exceptions
made explicit, and possibly some of the critical questions asked).
The pragma-dialectical scheme set, summarised in (van Eemeren et al2002) as comprised of symptomatic, causal and analogical schemes can be
represented in the AIF Forms ontology in the usual way, with instances fulﬁlling the constraints and properties of those forms as with other schemesets
already characterised, including those based on Walton et al.’s work (2008).
Instances of schemes are captured by RA-nodes, and the critical questions
correspond, as they do with schemes from other sources, to a variety ofstructural patterns including implicit premises (I-nodes) for presumptions,
implicit conﬂicts (I-node plus CA-node) for exceptions, and implicit undercutters (I-node plus CA-node plus I-node complex): Rahwan et al. (2007)
oﬀer some examples of these patterns.
Critical questions form a key part of the machinery of argumentation
schemes, and the dual argument1/argument2 nature of schemes and criticalquestions has been remarked upon previously (Reed and Walton 2007). On
the one-hand, schemes and the presumptions and exceptions that the criticalquestions embody have a distinctly argument1 character, in that they structure the connections between argument1 components. On the other hand,critical questions are inherently argument2 as they need to be asked in orderto ‘ﬁre’. According to the pragma-dialectical theory, the asking of criticalquestions is controlled by an intersubjective procedure. Though the resultsof that procedure correspond to RA nodes and their connected I-nodes, theprocedure itself is a part of the dialogical process of critical discussion – in
23

Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
just the same way that Reed and Walton (2007) advocate including a ‘Pose’
move into a simple dialogue game in order to accommodate the posing of
critical questions. It is to the characterisation of these dialogical issues that
we turn next.
4.2. Towards a critical discussion dialogue game protocol
Drawn from the ﬁfteen rules for a critical discussion and the speechacts that may (or should) be performed by interlocutors in the four stagesof a critical discussion, we can characterise the routes along which a dialectical exchange can develop. These possible routes are visualised as a directed graph (or ﬂow-chart) in Figure 5. The discussants start out at the
top with one party advancing a standpoint in the confrontation stage. Following the ideal procedure of a critical discussion the discussants can takevarious routes by performing certain speech acts at speciﬁc points during
the discussion to move through the opening and argumentation stages andend up in the concluding stage at the bottom of the graph. Momentarily wewill treat the intersubjective procedures as ‘black boxes’, leaving it to thediscretion of the discussants to determine the process therein and outcome
thereof. These intersubjective procedures are shown as oval nodes in thegraph. As is indicated in section 2.4 pragma-dialectical theory does provide
insight into these procedures and adding them will be one of the next tasks
in the venture of correlating the pragma-dialectical framework to the AIF.
Another proviso we need to make is that in our current tentative take we
do not distinguish between the discussion roles and the parties that initiallyadvance a standpoint or doubt it. Remember that either the proponent of
the standpoint or the challenger can assume the role of protagonist (or antagonist) in the discussion stage, but ordinarily it will be the proponent of
the standpoint who will actually argue for it. Another assumption we makeis that the standpoint is positive (i.e. +/p) and is only faced with doubt,
not with a contradictory stance. If the challenger would actually take theopposite standpoint instead of merely doubting it, two separate discussions
will have to be completed in order to test both the positive standpoint (+/p)
and the negative one (–/p). This will solicit a problem of order for the discussants who will have to agree which of the two discussion they will engage
in ﬁrst – and should not be taken as a problem of choice where settling the
one dispute would automatically settle the other.15 At present this fork in
15 Remember that a standpoint can only be constructively defended. Cf. (van Eemeren
and Grootendorst 2004, p. 141) for the problem of order (not choice) in a mixed or multiple
difference of opinion.

24

Correspondence between the Pragma-Dialectical Discussion Model and...
the confrontation stage of the discussion has not been incorporated into theﬂow-chart visualisation of the protocol yet. Catering the protocol for a negative standpoint would be done by allowing for a substitution of the current
positive standpoint (+/p) with a negative standpoint (–/p) and requiring
the force of the argumentation not to be justiﬁcatory for the standpoint
but rather refutatory. For the sake of simplicity we will nonetheless stickto characterising a single non-mixed diﬀerence of opinion in which a positive standpoint is at issue. Similarly we assume the discussants have noproblem understanding each other’s utterances and therefore have no needfor performing or requesting usage declaratives – which the rules for a critical discussion do allow at any moment (see rule 15 in (van Eemeren and
Grootendorst 2004, p. 157).)
Each node in Figure 5 represents a locution performed as indicatedby parties 1 or 2 or by both and with its particular discursive function.
The edges between nodes represent routes that discussants may take. The
ﬁrst two moves in the discussion will be party 1 advancing a standpoint
which allows party 2 to respond to it by casting doubt. Of course in actual
discourse interlocutors have the opportunity to perform many more locutionary acts than those shown here. The protocol expressed through thechart only and exactly covers the locutions and locution-pairs which areargumentatively relevant for the dialectical procedure of the critical discussion.16 Any digression from this procedure will be irrelevant to reasonably
resolving the diﬀerence of opinion and is not part of the critical discussion
procedure. That is to say the protocol presented is normative. For example
the discussion party 1 has the possibility to not advance any argumentation
and retract his prior standpoint (eg. for the sake of being done with it.)This could be regarded as a move heading directly to the mutual decision
to terminate the discussion at the bottom of the ﬂow-chart. But as the discussants did not ’play by the rules’ of a critical discussion this path has notbeen incorporated into the protocol. Such a move would mean there never
was a critical discussion to begin with: the standpoint’s merits were never
put to the test.
A possible diﬃculty in the procedure represented in the protocol is themove from the antagonists’s challenge to either the intersubjective inferenceor the explicitation procedure. As it stands the ﬁrst route has to be taken
iﬀ the argumentation was both fully externalised and dependent on logicalvalidity in its potential transfer of the acceptability of the premises employed
16 With the current exclusion of the usage declarations allowed by rule 15 in an attempt
to maintain a more-or-less comprehensive chart.

25

Jacky Visser, Floris Bex, Chris Reed and Bart Garssen

Figure 5. The (simplified) dialogue protocol of a critical discussion
as flow-chart

26

Correspondence between the Pragma-Dialectical Discussion Model and...
to the standpoint. This approach appears to be in line with (van Eemeren
and Grootendorst 2004, pp. 148–50). Nonetheless when we regard the reconstructive and interpretative steps available in the analysis of argumentative
discourse it appears to be possible to evaluate argumentation that is notpresented as fully externalised on the basis of its logical validity. In the absence of pragmatic factors that would suggest otherwise, the analyst can use
the transformation method of addition to add any unexpressed premise(s).
Such maximally reasonable (charitable) reconstruction is justiﬁed because
the interlocutors are taken to be bound by the communicative principle ofco-operation therefore performing speech acts aimed at the goal of resolving
the diﬀerence of opinion. (van Eemeren and Grootendorst 2004, pp. 115–118)
The protocol could be amended accordingly (i.e. by allowing the path[challenge force of argumentation] – [intersubjective explicitation procedure]– [intersubjective inference procedure].) This would warrant the question
whether in the light of the recent developments in non-monotonic and defeasible logics the strict separation between the intersubjective inference andtesting procedures is still viable or even necessary. Although from the perspective of computational complexity ineﬃcient the current protocol allows
for the same functionality as a more elaborated procedure which takes theanalysis through the logical minimum – the bare-bones needed for coherent
inference – and pragmatic optimum – dressing the bare-bones to account forthe contextual discursive embedding – into account. An interlocutor could
retract argumentation which has failed on the inference procedure side inorder to subsequently re-advance it either in fully externalised form or as
not based on logical validity this time around. Similarly an analyst can use
this method to end up with a ﬁtting maximally reasonable evaluation.
4.3 The protocol and locution-pairs in the AIF
By regarding the pragma-dialectical discussion procedure as a dialogue
protocol Figure 5 shows that locutions come in pairs where the ﬁrst might
be followed up by one speciﬁc or possibly of choice of several successor
locutions. Some of the pairs are of more interest than others and by meansof example we will characterise six of them in terms of Transition Schemes in
the AIF+ ontology. As a result of the universality of the language of the AIF,
some of the intricacies of the pragma-dialectical speech acts and critical
discussion model need to be treated as calculated properties or left out
altogether. Subsequent studies could investigate these omissions further toattempt a more precise correspondence.
A discussion starts with one of the parties advancing a standpoint. The
other party may then accept the standpoint, in which case there will be no27

Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
critical discussion. The more interesting thing to do, from an argumentative
perspective, is to doubt the standpoint. Consider the two locutions advancestandpoint and cast doubt in Table 4. In our characterisation of the locutions,
we present them in a “semi-formal” way. In Table 4, pi stands for the party(or player if we see the discussion as a dialogue game) that advances the
locution.
Locution name

Advance standpoint

Cast doubt on standpoint

Formatpi: standpoint S

pi: doubt S

Precondition description The propositional content p of S... none
– ...is not in the common starting
points– ...has not been the content ofanother standpoint S’ in the same
discussion
Postcond. description

pi is committed to (defend) S

none

Table 4

So in order to advance a standpoint, the propositional content p of thestandpoint cannot be in the common starting points because the standpointshould in principle not be regarded as fully acceptable (or accepted for thatmatter) by the other (cf. van Eemeren and Grootendorst 2004, p. 191, commandment 2).17 Furthermore, advancing a standpoint commits the party to
defend this standpoint. (Houtlosser 1994) Notice that there are no pre- andpostconditions on the individual cast doubt locution. Rather, any conditions
on this locution are part of the transition scheme; the characterisation in
Table 4 leads us to the ﬁrst pair of locutions in a discussion that can bemodelled as such a scheme in AIF+, viz. Table 5.
Scheme name

Advance Standpoint → Cast doubt on standpoint

Formatpi: standpoint S → pj: doubt S

Presump. description

pi 6= pj
Table 5

Notice that this way of characterising the transition prevents the straw
man fallacy by requiring that the standpoint doubted S is the same as theone advanced S (cf. van Eemeren and Grootendorst 1992, p. 124–31). The
transitional scheme adds to this the presumption that the doubt is cast by
17

28

Precondition (b) will be discussed below.

Correspondence between the Pragma-Dialectical Discussion Model and...
a diﬀerent discussion party from that which advanced the standpoint toaccount for the dialectical approach.
After casting doubt on a standpoint, there is essentially one possible
locution, namely to challenge the party who advanced the standpoint to
defend it, viz. Table 6.
Scheme name

Cast doubt on standpoint → Challenge to defend

Formatpi: doubt S → pi: challenge defend S
Table 6After a challenge, the other party may accept the challenge or the parties
may attempt to set the limits of their discussion by establishing the procedural rules for the discussion, common starting points, discussion roles andtermination criteria. On this subject, the literature is somewhat ambiguous:
whilst (van Eemeren and Grootendorst 1984, p. 99) seems to indicate thatfirst the challenge is accepted and then the limits are set, pragma-dialecticalrules 3 and 5 above (taken from (van Eemeren and Grootendorst 2004))
state that one is obliged to accept a challenge unless there is no agreementon the limits of the discussion. This would indicate that one only has toaccept after the limits have been agreed upon. Our (pragmatic) solution
is placing the discussion about common starting points and procedures ina meta-dialogue, as is indicated by the cloud-like part in Figure 5. However,in order to stay true to rule 3 we will presume that this discussion has taken place and there is an agreement before someone accepts the challenge todefend a standpoint. In other words, the agreement is a presumption in thetransition from challenge to acceptance (Table 7). A further presumption isthat the challenger is a diﬀerent person from the one who accepts.
Scheme name

Challenge to defend → Accept challenge to defend

Formatpi: challenge defend S → pj: accept challenge defend S

Presump. description– pi 6= pj– agreement on discussion roles and rules, starting points andtermination criteria
Table 7Note that the obligation created by the acceptance of the challenge does
not have to be explicitly rendered as, for example, a postcondition on theaccept challenge to defend locution, as the protocol ensures that the player
who accepts the challenge also advances an argumentation in favour of his
standpoint: from the accept challenge to defend locution it is only possible
29Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
to go to the decide to start locution (Figure 5) and after this locution, there
is only one possibility, namely for the party defending the standpoint toadvance an argumentation in favour of it (Table 8).
Scheme name

Advance standpoint & Decide to start → Advanceargumentation

Formatpi: standpoint S and pi, pj: decide start → pi: argue A

Presump. description– pi 6= pj– if S = (+/p), then A |∼ p
– if S = (–/p), then A |∼ ¬ phere, |∼ means so much as “p follows from A” under
the agreed rules.
Table 8

Notice that here, there are two locution types that are related to theadvance argumentation locution. The decide to start advance argumentationtransition simply denotes the sequence in which the locutions may be uttered: one cannot advance an argumentation before deciding to start a discussion. The relation between advance standpoint and advance argumentation,
however, is a functional (in this case argumentative) one: the argumentation A has to be a reason for or against the propositional content of thestandpoint, depending on whether the standpoint is positive or negative.
Note that an advance argumentation move can also follow a retract argumentation locution. This means that there is another transition to advanceargumentation viz. Table 9.
Scheme name

Advance standpoint & Retract argumentation → Advanceargumentation

Formatpi: standpoint S and pi retract A → pi: argue B

Presump. description– if S = (+/p), then B |∼ p
– if S = (–/p), then B |∼ ¬p
Table 9The presumptions of this scheme are slightly diﬀerent because the utterer of the retract and advance locutions is the same person.
So now we have a few diﬀerent conditions on the advance argumentation locution: it can only follow a decide to start or a retract argumentation
move, and it has to be in favour of one’s standpoint. In a pragma-dialectical
discussion, there is another condition on advance argumentation, namelythat the argumentation has not been advanced yet in this discussion (van30Correspondence between the Pragma-Dialectical Discussion Model and...
Eemeren and Grootendorst 2004, p. 153). This cannot be modelled as a presumption in the transition scheme in Table 9 (e.g. B 6= A), because the factthat the argumentation has not been advanced before does not just referback to the just-retracted argumentation advanced immediately before thenew one, but rather to all the argumentations advanced in the discussion
so far. Something like “all the argumentations advanced in the discussion
so far” is a typical example of a calculated property, which is represented
in the AIF as a simple I-node, in this case a precondition on the advanceargumentation locution.
Locution name

Advance argumentation

Formatpi: argue A

Precond. description

A has not been advanced in this discussion before.

Postcond. description

pi is committed to (defend) A
Table 10After an argumentation has been advanced, the antogonist can either
accept the argumentation or challenge the argumentation in various ways
(Figure 5). Hence, there are a number of transition schemes from advanceargumentation to the various challenges, Table 11 and 12.
Scheme name

Advance argumentation → Challenge propositional content

Formatpi: argue A → pj: challenge p

Presumption description – pi 6= pj– p is in A
Table 11
Scheme name

Advance standpoint & advance argumentation →Challenge justificatory force

Formatpi: standpoint S and pi: argue A → pj: challenge A |∼ S

Presump. description

pi 6= pj
Table 12

As discussed in section 4.2, the intersubjective procedures will be left
implicit in the current protocol. This means that there are no propertransitional schemes going out from the challenge argumentation locutions.
The next explicit locution is either a positive or a negative result regarding
the justiﬁcatory force or a positive or negative identiﬁcation of the propositional content (Figure 5). Now, in the case of a negative identification of p,
31

Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
a sub-discussion is started. This means that there is a transition of the typenegative identification of p → advance standpoint p. Here, the presumption
is that the limits set in the opening stage of the main discussion perseverein the sub-discussion. Also, each proposition p can be debated only once. Similar as for argumentations, this is determined in the preconditions because
it refers to a calculated property; recall condition (b) for the advance standpoint locution, which says that each proposition p can only be advanced asa standpoint once in a discussion.
In the case of a positive result or identiﬁcation, we can accept the argumentation or challenge some other part of the argument (e.g. the justiﬁcatory force if a proposition p was just positively identiﬁed). However, it isimportant that each proposition can only be questioned once and for any
argument can only be questioned once. Again, this can only be modelled
as preconditions on the challenge locutions: each challenge locution has asa precondition that the exact same challenge was not made before during
the discussion.
A discussion can only stop if the protagonist retracts his argumentation and subsequently his standpoint or if the antagonist after accepting theargumentation retracts his doubt. Important is that the retract argumentation A and retract standpoint S have as postconditions that the party that
retracts them is no longer committed to (defend) A or S, respectively.
The list of emerging locution pairs and their full speciﬁcation in terms ofpresumptions and the locutions’ individual pre- and post-conditions is by nomeans complete. We do believe such a full speciﬁcation could be construed
at a later moment. Let us ﬁrst summarise what we have done in this paper
before returning to the possibilities of continuing the current project.

5. Conclusion
Perhaps somewhat surprisingly, pragma-dialectical theory has, by andlarge, not been taken up in artiﬁcial intelligence, due largely to its heavyemphasis on the linguistic and pragmatic structures in natural texts which
are extremely challenging for computational accounts to handle. With theadvent of the Argument Interchange Format and its focus on representation of real arguments and therefore on pragmatic and illocutionary facets of argumentative discourse, connections between computational models and the pragma-dialectical approach are becoming possible in a moredetailed and thorough way than has previously been possible. This paper
has taken some initial steps to show how those connections can be made.
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Correspondence between the Pragma-Dialectical Discussion Model and...
In particular, our aim has been to show both the extent and the limitations of computational modelling of the foundational concepts within the
pragma-dialectical theory, including standpoints, discussion roles, starting
points, argumentation structures and argument schemes. With this basis
in place, we have then been able to demonstrate how the complex andsophisticated dialogue game of critical discussion can start to be modelled computationally in terms of the locution types and transitions between
locutions, and how that dialogue game can be connected to the underlying argument1 structures that are created, navigated and manipulated bythose locutions and transitions. This connection is coherent in both computational AIF terms and also in pragma-dialectical terms. What has beenachieved here is just a starting point: much remains to be done both inextending the AIF in the face of representational challenges posed by thepragma-dialectical approach (in terms of illocutionary characterisation ofargumentative speech acts, for example), and in continuing to build theconnection between AIF and the pragma-dialectical model (in terms of thetransitions in the game of critical discussion, for example). An exciting avenue for further investigation is then opened up in being able to explore
computationally more recent advances in pragma-dialectical theory suchas strategic manoeuvring (van Eemeren 2010). But this paper already demonstrates the potential and the value – for both artiﬁcial intelligence andphilosophy – of building a computational understanding of the pragma-dialectical approach.
Acknowledgements
Reed gratefully acknowledges the support of the EPSRC in the UK
under grant EP/G060347.
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Jacky Visser
Department of Speech Communication,
Argumentation Theory and Philosophy
University of Amsterdam, The Netherlands& International Learned Institute for Argumentation Studies
Spuistraat 134, 1012 VB Amsterdam
J.C.Visser@uva.nl
Floris Bex
Argumentation Research Group
School of Computing
University of Dundee
Dundee DD1 4HN Scotland, UK
ﬂorisbex@computing.dundee.ac.uk
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Jacky Visser, Floris Bex, Chris Reed and Bart Garssen
Chris Reed
Argumentation Research Group
School of Computing
University of Dundee
Dundee DD1 4HN Scotland, UK
chris@computing.dundee.ac.uk
Bart Garssen
Department of Speech Communication,
Argumentation Theory and Philosophy
University of Amsterdam, The Netherlands& International Learned Institute for Argumentation Studies
Spuistraat 134, 1012 VB Amsterdam
B.J.Garssen@uva.nl

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