The giant non-signers

 

 

The speech from this video is very well written. It clasps the main contentions with moderate exactitude, thereby adapting itself to the medium, it insists on some points then glosses over others and the visual side of it is simply attractive. Adopting a serious posture at most times (“It turns out my Pantene contains a chemical linked to cancer”, “My bathroom is a minefield of toxins” etc.), then inserting mild ironies, interjections (“Gross!") and suggestive gestures, this video is a handful of arguments. While watching it, however, I got more anxious by the minute. I was receiving so many pieces of information at such a rate that I decided to watch it again.

First, vagueness.  “Nasty”, “loaded with toxins”, “dozed”, “pre-poluted” are vage words. As important as they seem in general, they do not really matter in this specific situation. One could quibble over their meaning, but this would not affect the main direction of the video. Some other words and phrases like “linked to cancer”, “safe” or even “using” are vague in addition to being central to many of the arguments. These one should worry about. What does “linked to cancer” mean? I’m going to think like a five year old seal, but, in principle, if the truck transporting the products regularly passes by a mercury-processing factory, one could say – flippantly, yes – that that specific product is linked to cancer. The same, if some action does not equal being stabbed in the chest, one could say that (comparatively) it is rather safe. Or that a shampoo factory which offers beef burgers at lunchtime, is using beef burgers to produce shampoo. Estee Lauder may be using such-and-such chemicals to wash their cars. It still falls under ‘using to produce’.

Second, the rhetorical questions. I believe rhetorical questions in general cannot but be slippery. They use assumptions (as unexpressed premises) which, for some reason, are left aside by the interrogative form of the phrase. Why can’t one say it straightforwardly? [see what I mean…]. The rhetorical question from the airline analogy (“Would you fly in…”) made me think that we do not normally fly in chemicals, as we do in planes. If this is not a big difference, what is? [see…]. Again, the rhetorical question “Since when is oil an herb?” made me think the name of the shampoo is not “Only Herbal Essences”.

Many of these questions were actually answered. The video is just an overview of a more detailed and profusely footnoted text which can be found in PDF format here. I guess the unyielding scolder has a place to start from after all (not that it would certainly lead him somewhere).

But then, when Mrs. Annie Leonard started talking about those “responsible companies” which are “already putting safer products on the market”, I realized that the main standpoint of the speech was not “The-thing-X is such-and-such” but “The-future-action-X is such-and-such”. In other words, the standpoint was not evaluative, but deliberative. It did not (primarily) try to devaluate toxins, but (by means of this devaluation) to propose a course of action. What could this path consist of?

Hurry-scurrying form one link to another, I found The Compact for Safe Cosmetics. A summary of it can be found here, and more details from the same site here. In a nutshell, the Compact consists of six points (concerning safety, publicity, regulation) amounting to a pledge (!) which companies must have signed in order to appear on this list. The winners which underwent this hardship are not few! More than 1500 companies signed this pledge, which means that (at least at the moment of signing it) had wiped their slate clean. But then, if so many American companies are now allegedly in accordance with the European Norms, which struck everybody as way powerful and thus better, why the fuss? Answering this question should be easier if we think of two giant non-signers, Estee Lauder and P&G.

Progressivism

Those who are to young to get the whole point may check here for further references. I did.

What would artificial James Dean do?

i and j are our agents
In an environment τ, we have possible outcomes (or ‘states’), Ω = {ω₁, ω₂, ω₃, …}

The agents are self-interested, therefore they will have preferences over certain outcomes. In other words, If ω₂ and ω₃ are both possible outcomes in Ω, then as regards the utility (u) of ω₂ and ω₃, the following utility function (i.e. a way of representing preference) is possible:

 

ω₂ ≥_i ω₃

which is short for:

u_i(ω₂) ≥ u_i (ω₃)”

 

Of course, since we have two agents, they will both act upon the environment, so the simple answer e.g. ‘Every agents chooses the outcome ω_x with the best utility’ simply won’t do. “The actual outcome that will result will depend on the particular combination of actions performed. Thus both agents can influence the outcome.” (Woodridge, 2002, p. 109)

Let us note the possible actions each agent can perform ‘C’ and ‘D’. Obviously, in a real situation, (1) agents will have more than two actions available, (2) they will also have the possibility of ‘not-performing’, and (3) they might be able to see other agent’s action(s). So, the set of possible actions:

 

Ac = {C, D}

 

The change within the environment could then be formalized:

τ : Ac_i x Ac_j → Ω

Each Ac is then substitutable with either ‘C’ (cooperate) or ‘D’ (defect) so that we can now construct scenarios with different ‘sensitivity’ (i.e. different reactions to what agents do). For example, we can have scenario S1, where each combination of actions determines a different outcome (the first capitalized letter in the bracket represents i’s action):

[S1] τ(D,D)= ω₁ τ(D,C)= ω₂ τ(C,D)= ω₃ τ(C,C)= ω₄

Or, at the other extreme, we could have a scenario where, irrespective of the agents’ choices, the outcome stays the same (as long as they act, of course):

[S2] τ(D,D)= ω₁ τ(D,C)= ω₁ τ(C,D)= ω₁ τ(C,C)= ω₁

One can also consider an environment that is only sensitive to actions performed by one agent (i.e. it doesn’t matter what i does):

[S2] τ(D,D)= ω₁ τ(D,C)= ω₂ τ(C,D)= ω₁ τ(C,C)= ω₂

Now let’s assign certain utility to these possible outcomes. Woodridge (ibid.) takes the first scenario where each agent can influence the environment, as it is the more general one. We should then be able to consider agents’ preferences according to these utility functions:

u_i (ω₁) = 1 u_i (ω₂) = 1 u_i (ω₃) = 4 u_i (ω₄) = 4
u_j (ω₁) = 1 u_j (ω₂) = 4 u_j (ω₃) = 1 u_j (ω₄) = 4

We can then characterize agent i’s preferences thus:

ω₄ ≥_i ω₃ ≥_i ω₂ ≥_i ω₁

or, somewhat differently put,

C,C ≥_i C, D ≥_i D,C ≥_i D,D

Ok, now enough with the torturing jibber-jabber. The Game of Chicken. I’m rather sure most of you now what it means, but here’s a summary:

The adolescent dare game of chicken came to public attention in the 1955 movie Rebel Without a Cause. In the movie, spoiled Los Angeles teenagers drive stolen cars to a cliff and play a game they call a "chickie run." The game consists of two boys simultaneously driving their cars off the edge of the cliff, jumping out at the last possible moment. The boy who jumps out first is "chicken" and loses. source

 

Here’s the actual scene (with a touch of … techno?):

 

The twenty-something, delinquent agents ascribe utility according to possible outcomes. The worst thing that can happen is that both of them die (i.e. drive straight), so we can put (0,0) into the table below (which is called a payoff matrix). The best thing that can happen is that one of them wins by ‘not being the chicken’, that is, driving straight and letting the other agent swerve before you (4,1). Somewhere in the middle, the agent swerves first and all his twenty-something, delinquent agent friends call him a chicken for as long as he … operates. This, of course, is better than being dead, but worse than being macho.

 

	i swerves	i drives straight
j swerves	(2,2)	(3,1)
j drives straight	(1,3)	(0,0)

 

 

Agent i will have the following preferences (for ‘D’ = ‘defect’ = swerve, ‘C’ = ‘cooperate’ = drive straight):

 

D,C ≥_i C,C ≥_i C,D ≥_i D,D

This situation can produce two equilibria:  both die or both swerve. Ah, but remember. We are talking about ‘intelligent’ agents. We can then start making our agents as having beliefs and desires. The picture begins to complicate as the environment is apprehended in this manner. 

 

So, how should agent i play this game? It depends on how brave (or foolish) i believes j is. If i believes that j is braver than i, then i would do best to steer away from the cliff (i.e. cooperate), since it is unlikely that j will steer away from the cliff. However, if i believes that j is less brave than i, then i should stay in the car; because j is less brave, he will steer away first, allowing i to win. The difficulty arises when both agents mistakenly believe that the other is less brave; in this case, both agents will stay in their car (i.e. defect), and the worst outcome arises. (Woodridge, 2002, p.124)

 

 Agents have totties too, you know

 

Technorati Tags: James Dean,Game of Chicken,Game Theory,Multiagent systems,Michael Woodridge

Dialog Theory for Critical Argumentation

 

Title: Dialog Theory for Critical Argumentation
Author: Douglas Walton
Publisher: John Benjamins
Year: 2007

 

 

 

 

 

How do we ‘export’ argumentation to computer science? Is it possible in the first place? Do we have strong reasons to even try it? And how much autonomy are we ready to share with human-like computer systems when it comes to arguing? With these questions we are just scratching mousily the tip of an iceberg some choose to call computational dialectics (cracking, huh?). It must be said be said that the most influential philosopher to provide answers for these basic questions is undeniably Douglas N. Walton. Dialog Theory for Critical Argumentation (Walton, 2007b) is a book that organizes and reaffirms the importance of these, by now, well-trodden routes which a few decades ago felt queer and dusky.

Agency and artificial intelligence are still notions which hopefully the readers of this blog – shoulder to shoulder with the author – have trouble coping with. (Solidarity! That’s what I always say. Or l’esprit du corps, au pire, that’s what I’d say if I knew any … nevermind). However, it has been illustrated in earlier posts that someone interested in argumentation theory can (fortunately) skim over the technicalities without significantly damaging of the big picture. This is what this post will accordingly try to achieve: a big picture of what D. Walton dubs dialog theory[1] and its applications in computer science.

We are then ‘exporting’ argumentation. To argue is, notwithstanding, a complex language feature that humans learn to identify and process mainly through social practice and experience. The road back from practice to ‘form’ is therefore bound to be a difficult one. Aside from obvious regularities (e.g. assertions are made, questions are asked) and norms (e.g. argumentation proceeds by means of language behaviour), as Walton puts it, “the principles making for efficient communication are not explicitly stated anywhere” (Walton, 2007b, p. 18). What we need is a system, a theory. What would such theory speak of and what would it need in order to work?

1. A theory of reasoning

The central type of reasoning involved in argumentation could generally be described as defeasible (or plausible) reasoning . Enouncing this has some major advantages which can hardly be equated by the traditional (deductive or inductive) modes of reasoning: (1) agents constructed on these bases are more flexible, for the result of every inference is susceptible of being left out once the environment has provided conflicting information, (2) the analyst could model argumentation pertaining to values, i.e. evaluative statements, which are “inherently defeasible” (2007b, p. 95), (3) the ‘criteria’ of evaluation are not a set of monologic rules of inference but a set of (dialogic) critical questions formulated by a second party, and thus (4) the notions of ‘weight of presumption’ and ‘burden of proof’ are capable of being added to the picture. The Statements Proved Beyond any Doubt is an extinct species of outcome, which now require little (if any) attention.

Defining a ‘good argument’ by these lines is consequently not so much a problem of ‘form’ (though still an argument must be structurally correct), as a problem of ‘contribution to’ and ‘orientation towards’ the goals of the dialogue. At this point, we should note that most of the trailblazing was done quite early in the 70’s and 80’s, starting with Charles Hamblin’s work on fallacies[2]. With this, we arrive at the second requirement.

2. A system of rules

Much of what today we can name ‘dialectic system’ started with Hamblin’s chapter Formal Dialectics (Hamblin, 1970, 253-282), in which he set about positing a few ground-rules of language behaviour for speakers acting within the frame of a dialog. Although Hamblin’s intention was to produce a normative framework for the study of fallacies (Walton, 2007b, p. 167), he preserved a certain vagueness as regards the goal of the dialogues he studied.

“Sometimes Hamblin writes as though the purpose of a formal dialectical system is to seek or exchange information. At other times it appears that what he has in mind is more like what would be classified in chapter 1 as a persuasion dialog.” (2007b, p. 79, see also p. 73)

Hamblin constructed different types of dialogues, each with its peculiarities, but made no attempt to group these dialogues into a classification. The “Why-Because System with Questions”, for example, contains the following types of (allowed) moves: the making of assertions, the asking of questions, the retracting of commitments, the request for justification, the making of a resolution request. In a tableau-style view, such a dialogue would look like this:

Other attempts to model language by making use of formal systems could be cited (Hintikka, Barth & Krabbe etc.), although one should first notice that not all of them are fully oriented towards argumentation, i.e. a type of communication oriented towards persuasion. It shoud be noted that persuasion, within these formal systems, has little to do with the term as used in psychology, and it is understood rather as an outcome of specific moves in a dialogue framework: “persuasion, in this sense, refers to the respondent’s ‘conversion’ so to speak, or the change in his commitments. Before he was not committed to this particular statement, but now he is” (Walton, 2007b, p. 29, my italics).

Assuming that these systems work, that they are capable of providing the canons of ‘(procedurally) good argumentation’, what we now need is someone to follow such rules. Someone or, something.

3. Critical agents

I have indicated some elementary characteristics of agents in this earlier post. What I want to do now is follow Walton in adding some specific features an agent would need in order to function accurately in an argumentative situation. So besides autonomy, situatedness and feedback, a critical agent (i.e. an agent engaged in what Walton titles ‘critical argumentation’) must be, we could say, practical: it must be able to take action on the basis of practical reasoning. The goal-directed type of reasoning could be slightly formalized starting from Aristotle’s practical syllogism:

• G is my goal
  To bring about G, I need to bring about action A.
  Therefore, I need to bring about action A.

To complicate things a bit further, in order to arrive at a certain goal (G), the action (A) need not be sufficient; several other actions could be necessary in order to bring about (G). This means that the agent must also be tactical: not only that it should be capable of planning (i.e. developing a strategy) but it should be capable of recognizing the plans of others, a type of simulative reasoning called, quite intuitively, plan recognition. An agent should be capable of expecting certain pathways that the dialogue could follow and take (or avoid) those pathways according to its aims (Walton, 2007b, p. 190). Proactivity is an important feature in arguing as well as other types of communication, most notably deliberation. Several other features could be discussed. For instance, Walton speaks of a property called deceptiveness – or, the other way around, qualities of character (i.e. honesty, integrity etc.) – (2007b, p. 200) which could be useful for accounting for ad verecundiam and ad hominem arguments. Now, an agent with all these features will be useless. What he needs is some brothers with which to interact. Obviously, he cannot simply argue, he needs to argue with his peers. But before settling the issue of arguing, one should be able to resolve the more general problem of … communication.

4. Language

To put things in a nice, abbrev-ed manner:

Establishing a standardized agent communication language (ACL) is therefore a highly important part of MAS development. The first significant widely established attempt was KQML (Knowledge Query and Manipulation Language) proposed by the DARPA (Defense Advanced Research Projects Agency) knowledge-sharing effort. […] The most recent effort is the FIPA (Foundation for Intelligent Physical Agents). […] The standardized ACL developed by FIPA is similar to KQML. (Walton, 2007b, p. 135)

Now, before panicking, the reader should note that these languages are mainly based on more familiar notions like performatives (echoing the pragmatics of speech acts) or conversation policies (echoing Grice’s CP). Some differences exist, nonetheless. For example, FIPA is built on a BDI (belief-desire-intention) model, whereas pragmatics and implicature basically stand on a commitment-based model of human communication. Another thing, while any two assertions (for instance) could be pragmatically and semantically described as being identical, depending on the dialogue in which they occur, they can have different functions (in an information-seeking dialogue and persuasion dialogue).

5. Things to argue about

Once the above points have been reliably settled, implementing argumentation processes shouldn’t be rocket surgery. What one needs to stipulate is (a) a set of dialogue types – along with the notion of dialectical shift, and (b) argumentation schemes – along with their critical questions. The concept of dialogue type has been explained here and the problems involved in its usage here. The idea of dialectical shift – and the criteria of division between the ones that are based on embeddings and the ones that are not will be discussed in a subsequent post. As regards argumentation schemes, they are based on presumptive reasoning of the kind that shifts the burden of proof thus: “Each argumentation scheme has a matching set of critical questions. If an argument is put forward in a dialog by a proponent, and it meets the requirements of the argumentation scheme, and the premises are acceptable, then a weight of presumptive acceptability is thrown onto the conclusion. If the respondent asks an appropriate critical question, however, that weight of acceptability is withdrawn, until the question is given a satisfactory answer by the proponent.” (Walton, 2007b, 226, see also Walton, 1995, pp. 130-162). Further distinctions have been sketched here.

Switching to our Asimov-like foreshadowing, with the help of (Walton, 2007b, p. 191) we will imagine the following scenario. Let us call our agent Willie. Willie acts in his environment not as a program, but as an agent. This means not only that he is waaay smarter, but that he can justify his moves retroactively. In order to do that, he must have acted reasonably when he interacted with other agents, and pursued his goal(s) by means of persuading other agents either to commit to something or do something in some way. Willie’s friends are agents as well. And be sure they are not at all unintelligent. What they’ll do is try and achieve their own goals in what now becomes a dialogue. In this dialogue, positions are justified by argumentation which shifts the weight of presumptions by means of asking/answering critical questions. Believe it or not, Willie and his friends are even smarter than this. They can each simulate hypothetical variants of dialogues which could supposedly occur and establish a strategy based on the outcomes of such envisioned pathways. The strategy (or plan) will not be definitive, for as the dialogue unfolds, unexpected elements and moves from the other party can come into the battle. Which can hardly be called a battle, because what Willie and his friends are doing is argue cooperatively. In some instances, the type of interaction can even be seen as a clear-cut cooperation, when no set of opposite commitments is involved and some goals coincide. Nonetheless, as much as his friends, Willie can be capable of deceitful behaviour. In this cases, fallacies (and illicit dialectical shifts) occur.

Are you ready to let Willie argue for you?

 

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[1] I will stick to the orthography of ‘dialog’ as ‘dialogue’
[2] (Hamblin, 1970) For a small history of dialectic, see “What is dialectic?” here. I also found Hamblin’s chapter “The Concept of Argument” here.

Technorati Tags: Douglas Walton,Dialog Theory for Critical Argumentation,argumentation,AI,agent,multiagent systems,argumentation schemes,fallacies,presumptive reasoning,practical reasoning,reasoning

Frans H. van Eemeren, CADAAD 2008

Pragma-dialectical objections to Walton’s “dialogue types”

 

There are undoubtedly many points of intersection between (roughly tagged) ‘The Walton-Krabbe approach’ to argumentation and ‘The Amsterdam School’. Nonetheless, some equally salient differences are setting the two approaches off from one another. One of these differences has been brought up as a criticism formulated by pragma-dialecticians as regards the theoretical status of Walton’s “dialogue types” (Eemeren & Houtlosser, 2007; Eemeren et al. 2010). Beyond the scholarly etiquette, this could in fact be a very serious attack on Walton’s “pluralistic view” of argumentation. In this post, for the sake of brevity, I will assume some background knowledge on the reader’s part. However, feel free to consult these reviews before continuing: Walton, 1995; Walton, 2007; Eemeren & Grootendorst, 1984; 1992; 2004).

The two-fold criticism, introduced in (Eemeren & Houtlosser, 2007), is aimed first at the theoretical origins of Walton’s ‘dialogue types’ (Walton, 1995; Walton & Krabbe, 1995), and second, at the practical utility of the notion of ‘dialectical shift (from one dialogue to another)’. By and large, the same ideas are then elaborated in (Eemeren et al., 2010). I will henceforth refer to these two articles only by mentioning the years of their publication.

The status of ‘dialogue types’

“[O]n the one hand Walton assigns a normative status to dialogue types, but on the other hand he also appears to view dialogue types as empirical entities” (2007, p. 60). The principal function of dialogue types is to justify an evaluation; moves are judged critically with respect to the goal of the dialogue type in which they are identified to have appeared. In other words, “the goal of such modelling is decidedly normative” in the sense that dialogue types “prescribe which argumentative behaviour is correct” (2010, p. 117). A good argument is one that makes a contribution to the dialogue, or at least does not impede its development. A bad argument, is the one which blocks the achievement of the goal by infringing the rules.

Nonetheless, as the pragma-dialecticians observe, the concept of ‘dialogue type’ also purports to be close to the argumentative reality, that is, to be based empirically on descriptions of actual instances of argumentation. This is particularly noticeable in (Walton, 1995, p. 98): “In order to evaluate an argument as correct or incorrect, it is vital to know the context of the conversation in which this argument was used. [DT as criteria of evaluation] There are certain standard contexts in which arguments are typically put forward. To represent some of the most important and typical of these commonplace contexts, six normative models of dialogue are outlined below.” While words like ‘typically’, ‘standard’ and ‘commonplace’ suggest (indeed refer to) an empirical basis, that is, the fact that the types were generated by observing “empirical regularities”, the models are eventually labelled ‘normative’.

A natural question: “Why is this double function a problem?” The issue has been addressed, and neither Walton (1995) nor Walton & Krabbe (1995) seem to restrain themselves from positing simultaneously the two aspects of dialogue types[1]. There are two main grounds on which pragma-dialecticians base their objection: (a) it is a philosophical oversight not to distinguish the normative from the descriptive, (b) it is a methodological fault to analyze and evaluate argumentation from both sides. As regards the first, a rhetorical question posed in (2007, p. 61) is representative: “Are we talking ‘etically’ about an ‘external’ critical normativity based on analytic considerations of the theorist concerning the (goals and procedure of the) various dialogue types or ‘emically’ about an ‘internal’ empirically-based normativity amounting to a reconstruction of what is regarded sound in practice?”[2] In the study of language, it is one thing to observe regularities, patterns, another to observe certain norms underlying such regularities and yet another to stipulate external (etical) rules for the analytical purposes of the theorist. (2010, p. 120).

The methodological problems are briefly formulated in (2007, p. 61) and strengthened and illustrated in (2010, p. 121):

“Imagine, for the sake of illustration, a context of argumentation in which the discussants ‘typically and characteristically’ recognize certain characteristic syllogistic forms as valid, although every student who has completed an elementary class in logic would easily see that they are fallacious. Let us say Some A’s are B; Some B’s are C; Some A’s are C’s. Will such a persistent acceptance of this form of syllogism render it reasonable in this type of context?”

The outcome of ‘dialectical shifts’

The other part of the criticism involves the definition of fallacies as ‘illicit dialectical shifts’ (as one can observe, the two problems are highly inter-connected, since the criteria for deciding that a dialectical shift is licit or illicit stems from considerations about the context, i.e. about the types of dialogue involved in the shift). According to this view, “Some dialectical shifts […] are illicit, and these illicit shifts are often associated with informal fallacies” (Walton & Krabbe, 1995, p. 102). How does one distinguish the illicit from the licit shift? “Walton mentions as criteria for legitimacy of dialectical shifts that the new dialogue should not block the goals of the old dialogue and that the shift should be agreed upon by the speech partners” (2007, p. 62). To this, the objection goes as follows: “We wonder what the added value is of saying that a unilateral shift makes a dialogue move fallacious. Why does it not suffice to say that the move itself is inappropriate in the dialogue the parties are engaged in? Why does it not suffice to say that the move itself is inappropriate in the dialogue the parties are engaged in?” (ibid.) One possible answer is that the concept of ‘dialectical shift’ has explanatory properties, i.e. it serves to show how come some forms of fallacious reasoning come to be persuasive – they are legitimate in the new type of dialogue the arguer has shifted to (2010, p. 124).

Further issues

I thought these two were the more important criticism formulated by pragma-dialecticians as regards Walton’s “pluralistic view”. However, other methodological conundrums have been pointed out as well. For example, how can one decide what type of mixed dialogue is involved? Does the analyst identify a heated critical discussion as a critical discussion or as a mild eristic dialogue? This will most certainly influence the evaluation. And another thing, how can the deceitfulness of an illicit dialectical shift lay in the appropriateness in the new context, if the shift is unilateral? In other words, it is either that both parties are engaged in the shift (which makes it licit, and in some cases advisable), or that only one party has shifted (the other remaining blind) and the ‘persuasiveness of the fallacy’ cannot be activated since the blind party cannot apply the new required standards; if it could, it would render the move licit.

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[1] What is more, Walton & Krabbe (1995, p. 175) seem to suggest that this ambivalence is, if not inevitable, at least innocuous: “It would be nice if the answer were clear-cut and if each logic system had a tag on it, saying whether it is to be taken descriptively or normatively. But this is not the way things have worked out. All serious logic systems seem to have descriptive and normative uses, but to different extents. The point is that descriptive accuracy and normative content are both important and, moreover, interdependent” (cited in Eemeren et al., 2010, p. 121)

[2] The emic-etic distinction is borrowed from K. Pike, Language in relation to a unified theory of human behaviour (1967)

“On Bullshit”, with H. Frankfurt

Computing argumentation

 

Title: An Introduction to MultiAgent Systems
Author: Michael Woodrodge
Publisher: John Wiley & Sons
Year: 2002 (second edition)

 

 

 

 

 

 

The purpose of this tiny review is to set down some fundamental, albeit somewhat loosely explained, concepts from a subfield of computing known as multiagent systems. In particular, I will be happy if I will manage to follow the author in explaining: (a) what is a multi-agent system, (b) what are the basic concepts used in engineering such systems, (c) how come argumentation is relevant in this field. The further scope of this post is to furnish some background knowledge for an upcoming review of (Walton, 2007b).

First, how could one define agent and agency?

An agent is a computer system that is situated in some environment, and that is capable of autonomous action in this environment in order to meet its design objectives. (p. 16)

There is a certain consensus around the idea that autonomy is the basic feature of agency. An agent is thus capable of deciding itself what to do in order to achieve certain goals, these in turns being formulated by design. There are, however, major differences between an agent and a program – the latter too describable as a system which moves toward goals (p. 24). First, an agent is situated in an environment upon which it will not have full control. This ‘situatedness’ of agents gives rise to a second difference: besides not being fully accessible, environments are supposedly dynamic (i.e. they can change by influence of other factors/agents). What seems as a reasonable computation now may not be equally reasonable if applied ad infinitum, regardless of the modified parameters. Hence, the agent will not determine the environment, but influence it, by partially controlling it in interaction with other agents. With this, we arrive at the second basic feature of intelligent agents: their capability of social-like behaviour.

As the slogan goes “there is no such thing as single-agent system” (p. 105). In order to fulfill their goals, an agent must be capable of interacting with other systems. This makes it, as characterized in the Introduction of the book, “a natural metaphor for artificial social systems” (p. xi). Visually, a multiagent system could be depicted thus (click on the image):

Obviously enough, we will be principally concerned with the interaction between agents; how do agents interact, communicate, reach agreement, negotiate, compete, and – not the least – argue. Let us however say a few more words on the subject of agent design. First, any agent must have an ‘intentional system’ (I believe the concept is interchangeable both with ‘mentalistic model’ and ‘architecture’): “With this approach, we 'endow' agents with mental states: beliefs, desires, wishes, hope, and so on.” (p. 28). Now, this may seem like Asimov-ish, ‘what’s the matter, R2D2?’ way of getting things through. But, as it turns out, the two other available options are even less beneficial[1]. The BDI (belief-desire-intention) model is the most widely used, or anyway the most widely known[2]. We will discuss it in more detail in the review of (Walton, 2007b).

Lastly, the concept of ‘reasoning’ involved in agent design. As a consequence of the openness of the environment, the agent cannot function solely on deductive reasoning – which assumes that “the world will not change in any significant way while the agent is deciding what to do” (p. 54) The alternative is a model of practical reasoning defined as: “The particular model of decision making is known as practical reasoning. Practical reasoning is reasoning directed towards actions - the process of figuring out what to do” (p. 65). On a more deeper analysis, one could notice two distinct processes ‘inside’ (so to speak) practical reasoning: deliberation (what to do?) and means-end reasoning (how to do it?).

OK, these rough strands having been timidly pulled out, we could say a few words about the interaction between agents. The main issues will be discussed in the aforementioned future review. The most important point to be made, according to Woodridge, “is that when faced with what appears to be a multiagent domain, it is critically important to understand the type of interaction that takes place between the agents.” We say ‘type of interaction between’, we say ‘type of dialogue’ from (Walton, 1995) and (Walton & Krabbe, 1995). And indeed Woodridge (p. 155) turns to the latter for a typology of six dialogues: persuasion, negotiation, inquiry, deliberation, information seeking, eristic (and, many other mixed types).

Woodridge does not mention however any connection between these types of dialogue and argumentation schemes which might occur, hence the notion of argumentation, as we will see, is still kept at a rudimentary level. The ambiguity in ‘prove’, ‘justify’ or ‘establish’ seems of little importance: “an argument is a sequence of inferences leading to a conclusion: we write ∆ – ῳ, to mean that there is a sequence of inferences from premises ∆ that will allow us to establish proposition ῳ.” (p. 150) Acceptability, as Woodridge explains it, is a property of the class which the argument belongs. There are five classes of arguments

• Al The class of all arguments that may be made from ∆.
• A2 The class of all non-trivial arguments that may be made from ∆.
• A3 The class of all arguments that may be made from ∆ for which there are no rebutting arguments.
• A4 The class of all arguments that may be made from ∆ for which there are no undercutting arguments.
• A5 The class of all tautological arguments that may be made from ∆.

The difference between rebutting and undercutting could be rephrased, in a Toulmin-like terminology, as the difference between an argument attacking the conclusion (rebuttal) and one attacking the warrant (the relation between the data and the conclusion). Or, in computing-like terminology, where ∆ is the database, ῳ – the conclusion, and Γ – “is a subset of A known as the grounds, or support, such that Γ → ῳ”, then

“Let (ῳ₁, Γ₁) and (ῳ₂, Γ₂) be arguments from some database ∆. The argument (ῳ₂, Γ₂) can be defeated in one of two ways. Firstly, (ῳ_l, Γ_l ) rebuts (ῳ₂, Γ₂ ) if ῳ_l attacks ῳ₂. Secondly, (ῳ_l, T₁) undercuts (ῳ₁, Γ₂) if ῳ₁ attacks ψ for some ψ ϵ Γ₂.” (p. 151)

It took me ages to write that down…

I will stop here and state some of those obvious-facts we seem to so much enjoy. First, there’s more to multiagent systems than we’re able to grasp here. I say ‘we’. It’s me, actually. I have no background for further inquiry. Had I intended such diving in technicalities, I’d have failed pompously. Second, Woodridge’s account is not directly (better yet, not primarily) interested in the problem of agents arguing. The sketchy account here is the tip of an iceberg of many difficult, and possibly interesting problems to be solved.

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[1] When talking about what our little robot is doing, we could first opt for a description of the (its) physical stance, i.e., appeal to the physical configuration of the environment and to a sort of law-conditions-prediction matrix. Second, we could describe its design stance: “With the design stance, we use knowledge of what purpose a system is supposed to fulfill in order to predict how it behaves.” (p. 30). Now, with these alternatives, suddenly the intentional stance – considered strictly as means of abstraction, as a metaphor – feels prettier. As Woodridge notes,

“with very complex systems, even if a complete, accurate picture of the system's architecture and working is available, a physical or design stance explanation of its behaviour may not be practicable. Consider a computer. Although we might have a complete technical description of a computer available, it is hardly practicable to appeal to such a description when explaining why a menu appears when we click a mouse on an icon. In such situations, it may be more appropriate to adopt an intentional stance description, if that description is consistent, and simpler than the alternatives.” (ibid.)

[2] “The Procedural Reasoning System (PRS), originally developed at Stanford Research Institute by Michael Georgeff and Amy Lansky, was perhaps the first agent architecture to explicitly embody the belief-desire-intention paradigm, and proved to be the most durable agent architecture developed to date. It has been applied in several of the most significant multiagent applications so far built, including an air-traffic control system called OASIS that is currently undergoing field trials at Sydney airport.” (p. 82)

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“Willie-nilly”

 

I thought I’d serve a little appetizer before a review which, hopefully, will land here this week.

Some time in the not-so-distant future, you are having trouble with your new household robot. You say "Willie, bring me a beer." The robot replies "OK boss." Twenty minutes later, you screech "Willie, why didn't you bring me that beer?" It answers "Well, I intended to get you the beer, but I decided to do something else." Miffed, you send the wise guy back to the manufacturer, complaining about a lack of commitment. After retrofitting, Willie is returned, marked "Model C: The Committed Assistant." Again, you ask Willie to bring you a beer. Again, it accedes, replying "Sure thing." Then you ask: "What kind of beer did you buy?" It answers: "Genessee." You say "Never mind." One minute later, Willie trundles over with a Genessee in its gripper. This time, you angrily return Willie for overcommitment. After still more tinkering, the manufacturer sends Willie back, promising no more problems with its commitments. So, being a somewhat trusting customer, you accept the rascal back into your household, but as a test, you ask it to bring you your last beer. Willie again accedes, saying "Yes, Sir." (Its attitude problem seems to have been fixed.) The robot gets the beer and starts towards you. As it approaches, it lifts its arm, wheels around, deliberately smashes the bottle, and trundles off. Back at the plant, when interrogated by customer service as to why it had abandoned its commitments, the robot replies that according to its specifications, it kept its commitments as long as required - commitments must be dropped when fulfilled or impossible to achieve. By smashing the bottle, the commitment became unachievable.

Karl Popper’s typology of statements

 

It may be that Karl Popper’s Logic of Scientific Discovery  (1959) is not the last word in epistemology, but, as someone said about Kant not very long ago, you cannot go far wrong by studying it. Bearing this in mind, let us say a few words about Popper’s conception of various statements which make up scientific theories. Though the implications of the views briefly presented here are extracted and examined throughout the entire book, I will only touch upon the theoretical outset, which corresponds roughly with Chapters 3 and 4 of the Second Part (pp. 37-73)

Any theory which tries to account for some phenomenon in the external world has to be comprised of two kinds of statements: a singular statement [SS] (sometimes called ‘initial condition’) which describes a specific event in question and a universal statement [US] (sometimes called ‘hypothesis’, or ‘natural law’). This resembles the better known structure of a categorical syllogism, with its minor and major premise of the sort: “All un-suspended objects fall”, corroborated with “This ball is un-suspended” renders a prediction of a kind “The ball will fall”. Singular statements always contain, in some form or another[1], individual names and accordingly, universal statements are statements in which only universal names occur.

Within the class of universal statements[2], further distinctions could be made. First, Popper separates the numerical universal statements [NUS] from the strictly universal statements [SUS]. A numerical universal statement of the kind “All Finns speak Swedish” could in principle be verified by enumerating (hence the term ‘numerical’) all the elements in the class which makes the subject of the statement (i.e. all Finns). That is why, in a precise sense, the numerical universal statement is actually a singular statement, although it speaks of all the members in a class. It is singular because the class – ‘all Finns’, cannot be defined without reference to singular names (e.g. Finland), or the other way around, the statement could be defined by a conjunction of all the singular statements to which the “all-statement” refers.

Strictly universal statements, the ones which make up the so-called ‘laws of science’, can be described by no other means than references to universal names. One must be careful with this affirmation, for ambiguous nouns such as ‘mammal’ or ‘dog’ can be understood both as singular and universal names or concepts “it depends upon whether we wish to speak of a race of animals living on our planet (an individual concept), or of a kind of physical bodies with properties which can be described in universal terms” (Popper, 1959, p. 44). Strictly universal statements claim to be true regardless of spatio-temporal coordinates. To me, this is the fairly obvious distinction between what we normally designate by ‘any’ and ‘all’ respectively. ‘Any-statements’ (in reference to which we need not assume a bounded universe of elements) and ‘all-statements’ (in reference to which we must, as shown above, make reference to some spatio-temporal coordinates) are not mutually replaceable and would therefore serve one’s purpose. Popper makes no attempt to dissolve the ambiguity in ‘all’ by such distinction, so I will not use it any further.

With all this being said, a third distinction, arguably the most important one, is introduced: that between strictly universal statements [SUS] and strictly existential statements [SES]. This time, the statements are both, in the above sense, universal statements. The strictly existential statements are however significantly different: they assert that some event exists, e.g. “There are white ravens”. This statement could be described without reference to individual names, but could hardly be left under the same roof with a SUS. Popper calls them “there-is” statements, but most importantly, calls them non-empirical or “metaphysical”. Why?

With this, one must remember (or leaf back to page 17 for) the criterion of demarcation, i.e. falsifiability: a theory is empirical if it is possible for it to be refuted by experience. Can “there-is” statements, SES’s, be refuted by experience? They can’t: “[n]o singular statement (that is to say, no ‘basic statement’, no statement of an observed event) can contradict the existential statement, ‘There are white ravens’. Only a universal statement could do this” (p. 48) The explanation for this (although I feel the contention is quite sensible, if not self-evident) is that SES’s describe the existence of an event[3], while SUS describe the non-existence, i.e. ‘prohibit’ or ‘rule out’ the existence, of one. The negation of an SUS (‘All ravens are black’) is ‘Not all ravens are black’, and thus a SES, i.e. ‘There are non-black ravens’. This leads Popper to posit that “Whenever it is found that something exists here or there, a strictly existential statement may thereby be verified, or a universal one falsified.” (p. 49)

Short summary:

• singular (basic) statements = individual names (at least one)
  universal statements = universal names (all of them)
• numerical universal statements (NUS) = ‘All X’s [of a given place and time] are Y’s’ (in fact singular)
  strictly universal statements (SUS) = ‘All [i.e. any] X is Y’ (empirical)
  strictly existential statements (SES) = ‘There is at least one Y which is X’ (metaphysical)
• The negation of a strictly universal statement is always equivalent to a strictly existential statement and vice versa. = the non-SUS ‘Not all X are Y’ is the same as the SES ‘There is a non-Y X’
• SUS’s are falsifiable and SES’s are verifiable

“You’re overthinking this, man…”

 

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[1] Note that „individual names that occur in the singular statements of science often appear in the guise of spatio-temporal co-ordinates. This is easily understood if we consider that the application of a spatio-temporal system of co-ordinates always involves reference to individual names. For we have to fix its points of origin, and this we can do only by making use of proper names (or their equivalents). The use of the names ‘Greenwich’ and ‘The year of Christ’s birth’ illustrates what I mean.” (Popper, 1959, p. 43)

[2] We are, of course, talking about various kinds of synthetic statements, for “All women are women”, though universal by logical form, is not of much interest when we speak of empirical sciences.

[3] An event, in Popper terms, is seen as a class of occurrences. An occurrence is, in its turn, a class of basic (or singular) statements. So an event would be a class of classes of basic statements. If two basic statements are part of the same occurrence, they are equivalent. If they are part of the same event, they are homotypical (see pp. 67-71).

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What is dialectic?

 

This is a blog, we can afford ruthlessly ambitious questions, as the one in this title, for the prospect of an unsatisfying response can always be explained away by pleading non-academic informality. I don’t think this post will be a case in point, nor that other past entries were. I’m just juggling with the obvious. Note, nonetheless, Mr. Holmes’s fitting remark that “There is nothing more deceptive as an obvious fact”.

Douglas Walton offers one possible answer in chapter two of Dialog Theory for Critical Argumentation (2007b) – “The History of Dialectic” (pp. 47-89). As a historical account, the chapter is highly selective and thus, as a theoretical account, instructive for someone interested in possible definitions of “dialectic.

“Where did dialectic originate?” (50) Although one could cite possible reasons for attributing the idea and the practice of dialectic to Zeno of Elea (have some fun with this after finishing this post), Walton concludes that “it is not plausible that Zeno invented dialectic in the sense of the word meant by Plato or Aristotle.” So, in order to go back to the roots of dialectic, one could start with the Sophists (strangely, Walton notes here only the work entitled Dissoi Logoi), but then probably the safer option is to not go any further back than Plato’s dialogues. Formulating a definition is not yet advised for our part, but one could extract from the dialogues a few generally recurring rules (e.g. the respondent is expected to maintain a certain consistency in his answers) and two equally present goals: a) the negative one of “getting the bugs out of” one’s commitments by removing contradiction, and b) the positive one of “understanding the reasons behind” one’s beliefs (54). For now, we could say that Socrates established dialectic as a dialogue with (implicit) rules and (more or less specific) goals[1].

- Hi. How are you? Your argument is invalid.
- Fallacy!
- Too late.

Aristotle (On Sophistical Refutations, 165b4) offers the first definition of dialectical arguments as “those which, starting from generally accepted opinions (endoxa), reason to establish a contradiction”. Not much, of course, but one can already make some small yet meaningful notes: 1. dialectic is concerned with acceptability (thus a fallible form of argument), 2. Dialectic is concerned with consistency (i.e. non-contradiction) 3. dialectic is a social phenomenon (because “An endoxon is an opinion not only widely held, but that has some standing, and represents a serious view”), d) dialectic is critical (“reason to establish a contradiciton”). What’s more, Aristotle even brought about the first classification of types of dialogue: didactical, dialectical, examination and eristic. The ancient notion of dialectic reveals itself as follows:

It is an art of rational discussion in which a questioner and a respondent reason with each other by question and answer. It contains arguments, and chains of connected steps of argumentation running through the sequence of dialog. It is adversarial but also partly collaborative, and hence different from mere quarreling, as in eristic or sophistical argumentation (62)

Medieval times, medieval games. One in particular, called the Obligation Game, is quite relevant for a discussion on dialectic. It is actually the first attempt to somehow formalize what happens in a goal-oriented discussion. Walton makes a sketch of one version of it: “Questioner has the right to ask yes-no questions to the Respondent. The Respondent is obliged to give an affirmative or negative answer. At the beginning of the game, the Respondent has to accept some designated statement as his thesis. It tends to be a statement that is known to be false.” (66)

In the Enlightenment period, due mostly to Kant’s suspicion about the real profits of dialectics (I’m actually euphemizing what is actually Kant’s painting of dialectic as slightly autistic, guileful squabble). In modern times, while mathematics and mathematical logic were lion-heartedly pushing forward, the disregard continued. It was not until the second half of the twentieth century that the concept of “dialectic” – in the ancient sense of the word, leaving thus aside Marx’s and Hegel’s concepts – experienced what Walton calls a re-appearance. One could easily go for “re-birth”. Charles Hamblin’s Fallacies (1971), Nicolas Rescher’s Dialectics (1977), Else Barth & Erik Krabbe’s From Axiom to Dialogue (1982) and many other books and articles on the subject, were meant to rebuild dialectic(s) as a genuine theoretical and philosophical subject matter. The goal of formalizing the ‘dialectical reality’ was again stated and pursued. Later on, dialectic started influencing computer science, Artificial Intelligence, multi-agent system, software design etc.

From this historical tracking of the term, Walton extracts eight ‘components’ which, according to him, can be found – to a greater or less degree – in any forms of dialectic (pp. 75-80).

Dialectic is a branch of the science or art that is now called logic. The primary purpose of dialectic is to provide a method for analyzing and evaluating argumentation used for some purpose in a conversational exchange between two parties

1. It involves two participants reasoning with each other;
2. Any claim or argument is open to doubt and questioning/testing;
3. It is situational (in a conversational context) and pragmatic (oriented towards a goal);
4. There’s always an underlying opposition between parties;
5. Arguments are based on acceptance and commitment (not on knowledge and belief);
6. It is social (in the sense that the premises used are generally accepted opinions);
7. It has a normative (formal) as well as descriptive aspect;
8. It is concerned with the definitions one assigns to words;

Away from these, and not even all these (no. 8 is a bit strange and some would add a few more – e.g. an ideal of reasonableness is not mentioned), any ‘dialectic’ is ‘dialectic as understood by…’

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[1] This may seem slightly tautological (“dialogue with rules and goals”), but the point is to underline the possibility of observing such features. So one could rephrase it as “dialogue with specific rules and specific goals” (i.e. a systematic pursue of …) as opposed to “dialogue with random rules and random goals”. (i.e. an unreflecting, unconditioned conversation).

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Argument as rhetoric and rhetoric as argument? (II)

 

Title: Rhetorical Argumentation: Principles of Theory and Practice
Author: Christopher W. Tindale
Publisher: SAGE Publications
Year: 2004

 

 

 

Our earlier encounter with Tindale’s Rhetorical Argumentation (2004) was rather tranquil. I tried to expose the basic principles of the book with peace-loving passivity. Now, after the panorama, imagine a high-tech zoom on some more particular averments of the book. What will follow may appear as a finicky reading, but I am willing to assume that in exchange for the possibility that the underlined parts may have a degree of generality that goes beyond Tindale’s account.

 

1. The concept of “rhetorical argumentation”

While duly and readily acknowledging the three existent viewpoints on argumentation (logical, dialectical and rhetorical, pp. 4-8), Tindale is, I believe, and with all due respect, penny-wise and pound-foolish. Preying on the ambiguity involved in the concept of ‘argumentation’, the author leaves another, more important one slip right through the net. The one involved in the adjective ‘rhetorical’. ‘Rhetorical argumentation’ can mean both ‘rhetorical [approach to] argumentation’ and ‘rhetorical [type of] argumentation’ and, end-to-end, using both is highly disorienting.

When used, the syntagma “rhetorical argumentation” refers to a specific type of argumentation: the one which is rhetorical. This is the prevailing meaning found throughout the book. We learn that “rhetorical argumentation, through the situation it enacts, invites an audience to come to conclusions through its own experiencing of the evidence” (p. 24), “Rhetorical argumentation is dialogical. That is, there is a dynamic sense of dialogue alive in the context.” (p. 89). “If rhetorical argumentation can present two opposing arguments for consideration, then this shows that persuasion alone (of any kind) cannot be the goal” (p.185) A separate category of argumentation is then clearly being depicted. A type of argumentation which is invitational, not overtly antagonistic, constructed from the perspective of the audience etc.

But then, the entire book is about “argumentation as good communication” in which “arguers communicate with their audiences, and the positive results that emerge from the processes of anticipation, involvement, and response are integral to argumentative interaction” (2). It aims to show that (and how) “argumentation is essentially rhetorical” (19) and “how argument can be rhetorical” (20). This may seem like pretty much the same idea, but it actually implies quite different things. Chapter 4 explores and extracts the Bakhtinian theory of argumentation pointed at the constitutive role of the situation (96) and the “active role of the listener” (97). The arguer is “co-agent” with the situation. This is exemplified then with a Socratic dialogue: first, we apply the dialectical model which sees two-sidedness and turn-taking (pp. 91-93), then to the same dialogue, we apply the rhetorical [approach to] argumentation, and observe that “the goal first and foremost is no longer to seek a definition of piety but to reach an agreement of understanding” (106). “Rhetorical” is then an approach, rather than a type, it is a way of “paying attention” or “investigating”. In this sense, as regards the Socratic dialogue involved, Tindale notes that:

Such a sense of cooperation did not arise from the more traditional reading given to this exchange earlier in the chapter. Approached now in the light of our subsequent discussion, different aspects of the dialogue between Socrates and Euthyphro come to light (106)

So, again, we are being acquainted with an approach, a reading. This is actually made clear from the very beginning: “The rhetorical approach to argumentation insists that far more is involved and that the other two approaches miss what is really happening as communication” (6).

To make things even more complicated, “the rhetorical model” (of argument/of argumentation) could sustain the same ambiguity: it could be an ideal model of the type of argumentation that is rhetorical (the invitational, the one that makes the audience experience the persuasive discourse etc.), or it could be an ideal model of analysis. The latter sense could be observed as a case in point here: “what will emerge from the ensuing discussion is a model that is much richer than those implicated in current dialectical models, in the ways that it captures and describes the depth of the rhetorical context” (91). The model, then, captures and describes the argumentative reality.

Why does this matter? Because the two starting points cannot really be made and supported at the same time: I could either contend that there is a rhetorical “model” or “approach to” argumentation (and then an argument generally invites to co-production), or that there are some specific forms of argumentation, the rhetorical “type” or “mode” of argumentation (and then only some arguments are in the same sense invitational). With these implications, hardly can the two chapters (“Argument as Rhetoric…” “…and Rhetoric as Argument”) be seen as working towards the same theoretical thesis.

2. The dialectical injection

Let us zoom even more and check the second chapter mentioned above, “… and Rhetoric as Argument” (pp. 59-89). The point of this section is to answer the question ‘Can figures function/serve as arguments?’ and to answer it positively. Of course, in order to handle such an assignment, one must settle the definition of the subject (“rhetorical figures are devices that use words to make some striking effects on an audience”, 60), and the predicate, the ‘argument’. Understood rhetorically, an argument is not aimed solely at persuasion (“persuasion is but one use, and a minor one at that” (61). It aims at inviting towards change of perspective in order to achieve agreement, “creat[ing] insight and understanding” (54) and so on. In this sense, “Such argumentation does not prove a conclusion; rather it ‘enhances’ the conclusion, thereby creating a presumption in its favour. [...] What matters to us is the specific ways audiences are moved from considering reasons to considering conclusions. Some rhetorical figures, on some occasions, work in this way.” (63) I will get over the inescapable ambiguity of the terms ‘consider’ and ‘enhance’ (can I, for example, consider a conclusion but not accept it? is, in this case, ‘consider’ same as comprehend? If not, is ‘considering’ the same process as ‘accepting’? etc.)

It all starts after a quite analytical fashion. We have 3 conditions in order for a figure to serve as an argument: “(i) it has a recognized structure, (ii) its inner activity promotes the movement from premises to a conclusion, (iii) it has one of the goals of argumentation” Again, ‘to promote’ (as to enhance) is ambiguous, but I will not get into that.

Let us see one of the examples. In a nonfiction article, S. Rushdie writes about the publishers’ policies in these words:

“Let the market decide, too many publishers seem to think. Let’s just put this stuff out there. Something’s bound to click. So out the stores they go, into the valley of death go the five thousand, with publicity machines providing inadequate covering fire. This approach is fabulously self-destructive.” (75)

The author sees here an “analogy through an allusion” and contends that “both are used argumentatively [...] to encourage the audience to hold a certain perspective. And they are effective in doing this” (ibid.) As regards the analogy, things are simpler because the figure – to use Tindale’s words – “is a crossover device, doing double duty in the repertoires of both rhetors and arguers” The allusion, however, is much more subtle and for that reason much more intriguing: “The industry is self-destructive. How is it self-destructive? In the way that the infamous Light Brigade was self-destructive at Balaclava during the Crimean war, and the associated sense of folly. And this is made present through the allusion to Tennyson’s poem, explicitly invoked through the phrase he uses, referring to the valley of death” (ibid.) The allusion, in this case is effective at ‘making present’ the self-destructiveness.

So far, so good. But “Can we step beyond the argument from analogy itself and identify allusion as an argument when used in such way? I think the example allows that we can”

Condition (i): “allusion has a codified structure, it involves something being evoked without being expressly named”. Strike one. Condition (ii) “we see a movement from the premises to the conclusion, from a recognition/understanding already shared between arguer and audience to a recognition/understanding that it is proposed they should share”. Strike two? I do not think so. First, the equivocal couple “recognition/understanding”. If something is evoked without being expressly named, and if this is the allusion, what are the ‘premises’ and ‘conclusion’ being recognized and understood? Second, and more poignant, weren’t we leaving aside the analogy in order to pursue the argumentative values of the analogy? It still feels like we are talking about the analogy because Tindale continues thus: “And it works here to achieve an argumentative goal: to bring the audience to see the publishing industry as self-destructive”. Again, one can hardly move away from the ambiguity of “see”, but this is the description of an analogy (notice the metaphor-describing ‘as’). The further one move along, the more one realizes that we are still talking about the analogy: “When allusion is used as an argument, it would have conditions like the following: x is evoked by a discourse, x involves a connection with A that when made present increases the plausibility of A, therefore x is plausible” (76) This is the analogy, i.e. the content of the allusion, the ‘resemblance’ (“connection”) which allows for the comparison, not the allusion itself. The allusion has nothing to do with no connection itself, but with the way of presenting that connection: (again) “something being evoked without being expressly named”.

However, there’s an elephant standing at the table. Can you notice him? He’s big. And he’s described as “plausibility”. I thought we were talking about “seeing”, “understanding”, “recognizing” (all rhetorical features of the rhetorical argumentation, which – let us quote again – “aims at much more than persuasion”, 185). How has the dialectical-sounding “plausible” been injected? I had to read these paragraph a couple of times because the distance between what is said to be shown (that allusion is an argument), and what is shown (that the utilization of an analogy is meant to increase the plausibility of the construction “A is to B, like C is to D”). The two questions used for “assessing” the argument make it free from mist that the main character of the drama is the analogy alluded to, not the allusion: “1. Does the audience recognize what has been evoked (do they see the allusion)? 2. Is the connection between x and A sufficient to increase A’s plausibility?” One could rephrase them as: 1. Does the reader understand what’s going on? and, if he does, 2. Does he thinks it is a good analogy?

To conclude, I think what Tindale would have needed in order to prove his point is a case where something is made more plausible by virtue of being alluded to. In order to “serve as an argument”, we must see an allusion evoking, and by virtue of making something present by means of evoking (and not other) a conclusion is better perceived. Plausibility has little to do with the means one is trying to establish it. Plausibility is something we assign to the content of an argument, and it has little to do with the way it is being aimed. If the paragraph would have been presented in syllogistic form (no allusion being used), it would have been equally plausible, though far less striking as an effect. What allusion can do, then, is draw attention, make an argument more vivid, help the audience – in Tindale’s words – experience the argument. But when we start assessing and formalizing, what we are formalizing is the argument, not the means by which it has been made apparent. I think the subtle slide from one to another was made possible with constructions such as “x involves a connection with A that when made present increases the plausibility” which fail to function as a straight claim: is the plausibility increased by the connection (case in which we are talking quite classically about an analogy) or is the plausibility increased by the manner in which it has been made present?

The same ambiguity in the third “condition” is present when the author turns to praeteritio, another rhetorical figure proposed as “argumentative”. With x being an ad misericordiam argument, a praeteritio works like this:

An arguer, a, draws attention to x while professing to avoid it 
The audience is invited (implicitly) to construct x for themselves 
x, so constructed, increases the plausibility of a’s position” (81)

Same story, it is not clear whether x, as an argument, increases the plausibility of position P or x – as an argument which has been presented by the very phrases professing to avoid it, and by that very virtue of that manner of presentation increases the plausibility of position P.

Instead of a conclusion, I think comparing the two points made here would be useful. Because if 1 is the case, one could demand from the author to straighten things up and eliminate the ambiguity, but if 2 is the case, then the analysis, due to the same sort of instability, is simply wrong.

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