Values as the point of a story
Floris Bex, University of Groningen
July 3, 2013
Abstract
Stories can be powerful vehicles of persuasion, because they convince
not by imparting facts and rules, but rather by encouraging the rightchoices through a change in values. In this article I intend to lay theconceptual foundations for a mature theory of stories for value-based argumentation. The article discusses how stories can be used in argumentation, and how values can be seen as the point, or the conclusion, ofstories.

1

Introduction

Stories can be powerful argumentative vehicles: we often persuade not by imparting facts and rules, but rather by providing an interesting and convincing
narrative. This is particularly important when we are trying to convince others
to adopt particular values by which their actions are guided. For instance, it
is much more convincing to tell a child the story of The Boy Who Cried Wolf
instead of simply saying that they should not lie because then even if they tell
the truth, no one will believe them. Here, the story is meant to encourage rightchoices through a change in values rather than through a rule to be followed
and thus a value is adopted by the person rather than imposed.
The combination of stories and values in argumentation has been central to
the research Trevor and I have performed together since my visit to Liverpoolin 2008. With Katie Atkinson [11] we discuss abductive argumentation schemes
for arguing about past actions, where values serve as motives for these actions.
More recently with Bart Verheij [12] we have looked at how case-based reasoning(CBR) techniques from AI and Law [1] can be applied to arguing with factual
stories; thus we implicitly show how factual stories would fit in Bench-Capon andSartor’s [7] CBR model of reasoning with values. However, for various reasons
joint work on a full theory of persuasive stories for value-based argumentation
has never progressed beyond an exchange of notes and a short paper [9]. In thisarticle I intend to lay the conceptual foundations for such a theory.1
1 Interestingly, my work on the first version of this article for Trevor’s Festschrift has given
impetus to new work with Trevor on stories and argumentation [10, 6].

1

In [9], we pose three important questions regarding the role of stories in(value-based) persuasion: (i) What is the relation between arguments and stories? (ii) What are the elements of a typical story? and (iii) When is a story
persuasive for a particular person? I will propose tentative answers to thesequestions, paving the way for future collaborations. The perspective of this article is clearly that of computational arguments, computational narratives andmulti-agent approaches to communication. However, formal definitions will be
kept to a minimum but possible formalisations will be indicated where appropriate.

2

Stories in Argumentation

Structurally, stories and arguments are different things: a story is a coherent
sequence of events, whereas an argument is a reason for some conclusion . However, a story can be used for a variety of different goals: to explain, to entertain,
to persuade and so on. Whether a story should be considered as an explanation,
as a source of entertainment or as an argument depends not on its structure but
rather on the intention of the author or speaker. This idea stems from speech act
theory [23]: it is the intention of uttering some locution the illocutionary forceof the speech act that determines how the contents of the speech act shouldbe treated. So if a story is told with the intention of persuading or arguing,
we can consider it to be an argument, a reason for a conclusion, whereas if it
is told with the intention of explaining we can consider it to be an explanation[15]. This is vital, as the criteria by which we judge arguments, explanations orentertainment are wholly different.
In Bex and colleagues’ hybrid theory [13] arguments are used to reason aboutstories. The hybrid theory is one of Inference to the Best Explanation (IBE),
in which observations are first explained by hypothetical stories and arguments
based on evidence are subsequently used to support or attack these stories. For
example, a hypothetical story about a shooting can be supported by witnesses
stating that it was the suspect who shot the victim. However, the suspect’s own
denial of the shooting counts as evidence that attacks this story. Ultimately,
the objective of IBE is to find the best explanation, that is, the one that is
supported by the greatest number of evidential arguments and attacked by theleast number of evidential arguments. Figure 1 shows a stylised picture ofarguments supporting (closed arrow) and attacking (open arrow) elements in astory.
Another example in which arguments and stories are closely intertwined isin Case-based Reasoning (CBR). The field of CBR in Artificial Intelligence [17]essentially stems from the early work on story understanding [21]. Ideas fromthis early work were later on used in formal approaches to legal CBR in AI
and Law [2, 1]. In this work, cases are collections of factors, stereotypical factsituations with legal relevance, such as plaintiff was pursuing his livelihood orplaintiff was not in possession of the animal in cases relating to the chase andownership of game. Recently, the work on CBR has come full circle. Bex and2

storyargumentargumentargument

Figure 1: Arguments supporting and attacking a story
colleagues [12] focus on factual stories, which are very similar to legal cases inthat both stories and cases present a coherent set of facts; the main differenceis that in legal cases the elements of the case (factors) are somehow legally
relevant, whilst this is not a requirement for stories. Thus, the argumentative
moves of legal CBR [1] can be used to explore similarities between stories inan argumentative way. For example, it can be argued that Hamlet is similar to
Cavelleria Rusticana, as in both stories one man (Hamlet / Turrido) defends
himself because he is attacked by another man (Laertes / Alfio). However, thissimilarity can be countered by arguing that in Hamlet the attacker, Laertes,
was acting to avenge the death of his sister Ophelia, whilst Alfio did not havea similar reason to attack Turrido. Figure 2 shows a stylised representation of
two such arguments.
story A

story B

story A

story B?

argument (cite precedence):“story A and B are similar”

argument (distinguishing):“B misses an important element of A”

Figure 2: Arguments about the similarity of stories
The work on the hybrid theory and the work on arguments and stories in
CBR focus on arguments about stories: in the hybrid theory arguments areused to reason about the truth of a single story, and the CBR approach uses
arguments to reason about the similarity of multiple stories. However, as was
discussed above, it is also possible to use a story as an argument, that is, propose
a story as a reason for some conclusion. In the case of IBE, once the best
explanation is inferred, we can infer further conclusions from this explanatory
story. For instance, from a factual story containing the elements S shot V
and S shooting V caused V to die we can infer both that S intended to kill V
otherwise S would not have shot V and that S killed V, which together leads
to the conclusion that S murdered V. Here the elements of the story serve as
the conditions of legal rules [14] and thus as premises to an argument (Figure3). So in addition to reasoning about stories we can also construct argumentswith stories.
3

conclusion
argument

story

Figure 3: Drawing conclusions from elements in a story
CBR also involves both reasoning about and with stories: first we inferthat story B is similar to story A’ from which previously conclusion C wasinferred (reasoning about stories, left side of Figure 4). This then allows us
to infer C from B (reasoning with stories, right side of Figure 4). In legal
CBR, the conclusion C that we want to argue for is typically a legal conclusion.
For example, in Pierson vs. Post, plaintiff was chasing a fox and defendantinterrupted the chase, killing the fox and claiming it. It was concluded thatplaintiff had no right to the fox since he had not gained possession of it. A
similar case was Young vs. Hitchens: in this case plaintiff, a fisherman, wasclosing his nets when defendant sped into the gap and caught the fish in his
own nets. The two cases are similar because in both cases, plaintiff was notin possession of the animals. Hence, by citing Pierson v. Post as a precedent
we can draw the same conclusion in Young v. Hitchens, namely that the caseshould be decided in favour of defendant.
C

conclusion

conclusion

argument

story AC

argument

similarstory B

story B

Figure 4: Drawing the same conclusion from a similar story

2.1

Value-based argumentation

Values have been incorporated into formal argumentation frameworks by Trevor[5]. The basic idea is that accepting a particular conclusion promotes or demotes
some abstract social or cultural value such as liberty or equality. In a sense,
people’s world views can be said to represent an ordering of such values; forexample, a Democrat will generally prefer equality over liberty, whilst for a4

Republican this will be the other way around. Whenever a person has to choose
between competing arguments, they choose the argument that best matches
their value ordering, that is, the argument that promotes their favoured value.
Atkinson and Bench-Capon [5, 4] show how discussions about moral issues
can be represented as practical reasoning with values. Such arguments are of
the following form2 :I have goal G.
Performing action A in situation S will realise goal G, which will promote
some value V.
Therefore I should perform action A.
The idea is that by performing an action and reaching a goal, a value ispromoted. For example, if you find a wallet with a large sum of money you
can bring it back to its rightful owner (promoting honesty) or take out themoney (promoting wealth). The choice whether or not to perform an action is
ultimately governed by one’s value ordering (i.e. whether honesty or wealth ispreferred).
Atkinson and colleagues’ model does not capture reasoning with stories orcases: the premises of arguments are simple propositions. Value-based reasoning
with cases has been tackled, however, by [7], who present a model of legal CBRin which combinations of individual factors and decisions promote values. So, forexample, if based on the factor plaintiff was pursuing his livelihood we would
decide for plaintiff, the value productivity would be promoted. Thus, a casepromotes all the values that are promoted by its individual factors. Note that
we can essentially consider CBR to be a model of practical reasoning [3], where
the action is making a legal decision (e.g. “decide for plaintiff”). In this way, thereasoning in Bench-Capon and Sartor’s model can be interpreted as practicalreasoning with more complex situations and multiple values: given situation
x1 , . . . , xn , where xi is a factor, performing action A (deciding for plaintiff ordefendant) promotes values v1 , . . . , vn , where vi is the value promoted by the
combination of factor xi and decision A.

2.2

Issues for Stories in Value-based Argumentation

The objective of this article is to lay the foundations for a model in which stories
can be used to influence the actions of others. The current work on stories
and argumentation discussed above shows that stories can form the basis ofarguments by providing the conditions for the application of one or more rules,
and that these arguments can promote values in the usual way. However, there
are a number of open issues.
First, note that the existing approaches mainly use stories to infer legal
conclusions such as “the defendant is guilty” or “the case should be decided forplaintiff”. The legal rules used to infer these conclusions can be derived from
2 The exact argumentation scheme used by Atkinson and Bench-Capon is slightly different;
here I have adapted it into a slightly abbreviated standard form.

5

previous decisions (in the case of CBR, 4) or found in legislation (for models
that adhere to a more continental legal approach, 3). An important aim is tofigure out which non-legal conclusions we want to derive from stories and which
inference rules allow us to do so. The work on practical reasoning provides some
important basics here: if stories are told to influence the behaviour of others,
they can be considered as premises to arguments for practical reasoning. In
other words, we might use stories to infer the standard conclusion in models forpractical reasoning, namely action A should be performed.
One issue with treating value-based reasoning with stories as standard practical reasoning is that current conceptions of practical argument are mostly
concerned with specific, goal directed actions (e.g. “stop eating cake”, “install
speed cameras”, “decide for plaintiff”). However, when one tells a story suchas a parable or a fable, the objective is often not to influence a single future
action but rather the way in which someone lives their life in general. Basically,
what one is trying to accomplish by telling a story is a shift in values, a change
in someone else’s worldview, so the conclusions of arguments based on stories
should be the values or value orderings themselves, or at least a more abstract
rendition of actions which is not directly aimed at building a plan but rather at
providing the basic tenets for how one should live one’s life.
Another open question is exactly how stories serve as the premises of arguments for practical reasoning. As discussed earlier, Bench-Capon and Sartor’smodel (implicitly) uses cases as premises of practical arguments. So, given thesimilarities between stories and cases [12, 14], it should be possible to model
value-based reasoning with stories in a similar way; instead of one case setting
a precedent for which legal decision needs to be made in a similar case, a story
sets a precedent for how one should behave in a similar situation. What needs
to be determined now is which elements of a story cause it to be an argumentfor or against a particular value. For this, we turn to research on narratives andstory points.

3

The Structure and Point of a Story

Since Aristotle’s Poetics, there have been numerous theories about the elements
and the structure of narratives, mainly in literature theory. The first formalisation of the structure of stories came from Vladimir Propp [18], who identified standard event types and structures for folk tales. Following Propp’s
work, researchers from the field of cognitive psychology and artificial intelligence became interested in story structure, mainly with the aim of defining andautomating story understanding. Influenced by the work on generative grammars, researchers such as [20] developed so-called story grammars, which express
the structure of stories as a Context Free Grammar. For example, most story
grammars divide a story into a series of episodes (story −→ episode∗), each ofwhich has a basic goal-driven structure (episode −→ setting + goal + action +consequence). Others, most notably [21], argued that whilst stories consistof goal-driven action sequences, story understanding is more content-driven, in

6

that more specific information in the form of scripts is used when understanding
stories. Scripts model the way things tend to happen in the world; for instance,
the restaurant script lists the roles (customer, waiter) and sequence of events(ordering, eating, paying) for a typical restaurant visit.
Wilensky [27] argued against story grammars and scripts, saying that a pieceof text can only be a proper story if it has a point. Wilensky distinguishes between external points, goals a storyteller might have when telling a story such as
persuading someone or communicating information, and internal points, partsof the story text that generate interest. Wilensky’s theory mainly focuses oninternal points. As an example of an internal point, consider the following sequence of events: “John loved Mary. He asked her to marry him. She agreed,and soon after they were wed. Then one day John met Sue, a new employee
in his office, and fell in love with her”. This text has an internal point, thatis, there is a dramatic situation that involves goals and the interaction between
them. In the example, a new goal (the love for Sue) interferes with an old goal(the marriage with and love for Mary). So, according to Wilensky, the pointof a story is a summary of the events that comprise interesting (“dramatic”)
goal relationships in the story (“John loves someone but is already married tosomeone else”). Wilensky thus argues that the dramatic content in a story canbe found by looking at the relationships between the goals of the various characters. Wilensky’s idea of dramatic content, however, can be further generalisedby taking into account Schank and Abelson’s scripts: often, it is a deviation of
the standard script that counts as “dramatic content”. In the example, people
might expect John and Mary to live happily ever after, as the (original) idea
behind marriage is that it lasts “until death do you part”. This script-based
approach to dramatic content allows for a broader definition of the term. For
example, in Searle’s Chinese room story [24], the Chinese Room satisfies theTuring test (i.e. it answers questions in a seemingly intelligent way). Our standard script is that if something satisfies the Turing test, it can be said to be
intelligent. Searle’s dramatic twist is then that there actually no intelligence
being engaged even with a human inside [10].
Wilensky thus argues that the dramatic content in a story can be foundby looking at the relationships between the goals of the various characters.
Wilensky’s idea of dramatic content, however, can be further generalised bytaking into account Schank and Abelson’s scripts: often, it is a deviation of thestandard script that counts as dramatic content. In the example, people might
expect John and Mary to live happily ever after, as the (original) idea behindmarriage is that it lasts “until death do you part”3 . This script-based approachto dramatic content allows for a broader definition of the term. For example,
in Searle’s Chinese room story [24], the Chinese Room satisfies the Turing test
(i.e. it answers questions in a seemingly intelligent way). Our standard script
is that if something satisfies the Turing test, it can be said to be intelligent.
Searle’s dramatic twist is then that there actually no intelligence being engaged
3 However, considering the high number of divorces the standard script might nowadays be
marriage to A divorce marriage to B divorce. In this case the story would be contain adramatic twist if John and Mary actually lived happily ever after!

7

even with a human inside [10].
Schank and colleagues [22] also discussed points in the context of story understanding. They perceive points to be interplay between the speaker’s intentions
on how the listener should process the story and the listener’s ability to correctly process and categorise a story. For example, affective points are meant tochange the listener’s goals, explanatory points are meant to explain situations,prescriptive points are meant to present the listener with rules, argumentative
points are meant to persuade the listener, and so on. These point categories arevery similar to the differences in illocutionary force discussed earlier: a story
may be told with the intention of explaining, arguing and so forth4 . Very often,
this illocutionary force depends on the dialogical context in which a story is told
[19]. For example [6, 25], in the bible Jesus is often asked a question to which
he responds with a story, a parable: the story of the Good Samaritan is told
to answer the question “Who is my neighbour?”, and the story of the Prodigal
Son is told in response to the Pharisees negative comments on Jesus’ consortingwith sinners. Jesus tell these stories with the intention of explaining who canbe considered a neighbour, or why he consorts with sinners, and at the sametime these stories argue for a particular value or value ordering.
Dorfman and Brewer [16] provide a model in which the point of a story is nota structural characteristic of the story (as in Wilensky’s work) or specifically tied
to the intention of the speaker (as in Schank et al.’s work). Rather, Dorfman andBrewer argue that the point is a higher level concept, a moral or an “abstract
truth”. The point of many stories, such as fables, is about whether we shouldor should not exhibit certain behaviour, for example, “don’t be overconfident”,“be honest” and so on. The point of the story can be explicitly mentioned in
the text, as is often the case for the various renditions of Aesop’s fables where
the moral of the story is explicitly included. Take, for example, the tale of The
Boy Who Cried Wolf, which concerns a shepherd boy who repeatedly tricks
nearby villagers into thinking a wolf is attacking his sheep. After a while, awolf actually does appear, the villagers do not believe the boy’s cries for help,
and the flock is destroyed. Caxton’s medieval version this tale of ends with theexplicit point “For men bileue not lyghtly hym / whiche is knowen for a lyer ”.
In many cases, however, the point of a text is not explicit: mentioning thepoint of a story is often considered to be quite a thought-terminating clich. The
question is then how the contents and structure of a story influence its point.
Dorfman and Brewer try to answer this question by proposing and testing amodel of point comprehension. In this model, readers infer the point or moralof a story based mainly on the positive or negative valence of the story’s central
action combined with the positive or negative valence of the story’s outcome.
The central action of a story is the morally significant action of the story; forexample, lying in the case of The Boy Who Cried Wolf or being lazy andoverconfident in The Tortoise and The Hare. The outcome describes how thecentral action was resolved. Actions and outcomes can be perceived as positiveor negative (according to Western standards): lying is a negative action, losing
4 In fact, Schank and colleagues explicitly connect their work to Searle’s work.

8

one’s sheep is a negative outcome, being diligent is a positive action, winning arace is a positive outcome. In their experiments, Dorfman and Brewer presented
subjects with a variety of short fables. Base fables are the original versions,where positive actions are paired with positive outcomes and negative actions
are paired with negative outcomes. Reversed outcome fables were the base fables
with reversed outcome valences (e.g. the Hare wins the race), so a positive action
is tied to a negative outcome and vice versa. Neutral and no-outcome fables
had a non-morally significant central action or no outcome, respectively.
The experiments showed that in the case of base fables, subjects nearly
always (95%) correctly understood the moral point of the story correctly, thatis, the fable’s moral was understood as originally intended. For neutral andno-outcome fables, most subjects (93% and 85% respectively) could not finda point to the story. In the case of reversed-outcome fables, about 60% of
the subjects argued that there was no point to the fable. Of the remaining
40%, most subjects (40%) assigned a new, reversed moral point to the story
that coincided with the new outcome. For example, in the reversed-outcome
The Goose and the Golden Eggs, the farmer kills the Goose, as in the original
fable, but instead of losing his source of income is rewarded with a huge sumof gold. The new point assigned by subjects was then something like “greed
and impatience are good”. However, quite a lot of subjects (30%) replied thatthe reversed-outcome fable had the original point (e.g. “greed is bad”). This
is attributed to the “just-world” hypothesis: people will always believe that
good behaviour will or should be rewarded and bad behaviour will or should bepunished, even if a story tells them otherwise.
It seems that there are various ideas about what constitutes the point of astory: dramatic story content (“John loves someone but is already married tosomeone else”), the intention of the author (to argue for fidelity in marriage),morals in the form of a lesson about one should or shouldn’t do (“you should
not look at other women once you’re married”), or perhaps more abstract values
one should follow (fidelity).
The dramatic story content and the intention of the author are, in my view,not the point of the story but they play an important part in establishing thepoint of a story. So-called neutral stories, in which there is no dramatic resolution to some central event, are usually regarded as pointless. The intention of
the narrator, which can sometimes by gathered from the context, is also important as the above discussion shows. Finally, the knowledge and beliefs of thereader also guide the inference of a point from a story: deeply entrenched beliefs
influence the point that people read in a story (cf. the just world hypothesis),and a reader will identify more with a character who is in a similar situationor who has a similar world view. The point of the story is thus the interaction
between the structure and contents of the story and the knowledge and beliefsof the reader. The story teller intends the story to have such an interaction andthus change the knowledge and beliefs of the reader in a particular way.
Which knowledge and which beliefs are usual targets of storytelling? Thisof course depends on the type of story and the context in which it is used in[24], the point of the story is that “Syntax by itself is neither constitutive of nor
9sufficient for semantics” or, in other words, being able to manipulate strings ofsymbols does not mean that one understands the meaning of these symbols. In
this article I mainly discuss stories with an explicit moral, that is, stories thatare meant to teach us values and influence our behaviour. As indicated earlier,here the interest is not in stories that are intended to influence a rather simple,
single action but rather in stories that are aimed at influencing the (order of)
the values people believe in and live their lives by.

4

Stories in Value-based Argumentation

In section 2, it was discussed how stories can be used as arguments: if theintention of the speaker is to persuade someone using a story, they can argue forsome conclusion by telling a story. As the discussion in section 3 demonstrates,
this conclusion will be what is normally called the point of the story: a lessonon how we should live our lives, which values we should strive for. Clearly, thesetypes of conclusions are very close to the conclusion of a value-based practicalargument: action A should be performed to promote value V. Note that, as
discussed in the previous section, this conclusion is often left implicit, as stories
are as much intended to provoke thought as to lay down explicit rules.
The premise of the argument, the reason for performing the action, is in
this case the story itself. This story tells us what will happen if and when theaction is performed. The following provisional argument scheme for practicalreasoning based on stories can now be constructed:
Character x performs action A, which promotes (demotes) value V, and gets
positive (negative) results
Therefore I should (not) perform action A, promoting (demoting) value V.
The premise is the story, in which a character performs an action and gets a
certain positive or negative result, promoting or demoting a value. For example,
the boy lies about the wolf, demoting honesty, and gets negative results, namely
none of the villagers help him when the wolf does turn up. From this story, we
can conclude that we should not lie.
The above scheme presents a generic situation, in which a story is told andwe expect people to accept the conclusion. Whilst we can expect that, given astory, people can infer the conclusion that they should exhibit certain behaviour,
it is certainly not clear that people can be persuaded just by giving them a story.
Persuasion requires a person to somehow identify with the character in a story.
As an example, consider the parable of the Prodigal Son (Luke 15:11-32). In
this story, a father gives the younger of his two sons his inheritance before hedies. The son goes off and wastes his money, but after a while goes hungry
during a famine. The son repents and returns home, where the father holds
a feast to celebrate his return. The older son is angry that the father holds a
big feast for his wasteful sibling, stating that he never got such a feast eventhough he always obeyed his father and worked hard. The father reminds theolder son that everything the father has is the older son’s, but that they should

10still celebrate the return of the younger son as he has come back to them. As
a young student, identifying with the younger son, one might take from thisstory that it is not forbidden to make mistakes, as long as you can later see theerror of your ways. As a father, one might see this story mainly as a tale offorgiveness: no matter what your children do you should always forgive them.
So a story sets an example by having the listener or reader identify with oneof the characters. More precisely, the story acts as a precedent for the current
situation and thus, arguing with stories takes the form of Case-based Reasoning,as described in section 2.2:
Character x performs action A, which promotes (demotes) value V, and gets
positive (negative) results
I am in a similar situation as character x
Therefore I should (not) perform action A, promoting (demoting) value V.
This scheme effectively combines practical reasoning and argument fromanalogy. A similar scheme is Walton and colleagues’ [26] scheme for practicalreasoning from analogy, which says that if in situation S, action A is the right(wrong) thing to do and S’ is similar to S, then in S’ one should (not) do A. The
scheme proposed here is a more detailed version of this scheme, focusing on how
people are persuaded by stories. Furthermore, the idea of story similarity has
recently been explored in [12]. This work builds on the idea of story schemes [8]generalised patterns of events akin to scripts [21] for comparing stories: twostories are relevantly similar if both are an instance of the same story scheme.
The conclusion of the above scheme, however, still points to a specific action,
whereas we want stories to influence the (orderings of) values others use to live
their life by. This more general effect of arguments based on the above scheme
also influences the relation of these argument to the kind of value orderings
proposed by [5]. Where in standard practical arguments value orderings aremeant to allow us to choose between competing arguments, arguments following
the above scheme are meant to influence precisely these value orderings: values
attached to actions that lead to positive results should be preferred to values
attached to actions that lead to negative results. So we could further rewrite
the scheme as follows, focusing on the values instead of the actions.
Character x performs action A, which promotes (demotes) value V, and gets
positive (negative) results
I am in a similar situation as character x
Therefore I should (not) prefer actions that promote (demote) value V.

5Conclusions and future work

In this article, I have discussed the role of stories in argumentation and how thecontent of stories and their structure influence the arguments based on them. I
have shown that by combining ideas from practical and case-based reasoning, a
simple argumentation scheme can be constructed that captures, in my opinion,

11the essence of story-based persuasion. Because the work clearly builds on existing formal approaches to CBR and practical reasoning, further formalising andintegrating it with these approach should be fairly straightforward.
There are, however, still a number of issues that are somewhat harder tosolve. Simple stories such as Aesop’s fables usually have one protagonist anda clear action-outcome structure. However, when we start looking at, for example, parables things start getting more complex: the Prodigal Son has threeimportant actors, each with his own behaviour and set of values. Furthermore,
the positive or negative outcome is only one way to determine the point of astory. In the fables, the outcomes are quite clearly positive or negative. In
Biblical parables, they are less so: is the party really a positive outcome for theolder son? In such cases, the actual point of the story (i.e. the value promoted)
is often more dependent on context, intention of the narrator and expectationsof the hearer. In addition, more complex stories do not necessarily convince because the hearer is in a similar situation, but rather they convince by evoking an
emotion. For example, the parable of the Good Samaritan is not just meant topersuade people to help persons who have been robbed and beaten, but rather
to show mercy and compassion in all relevant situations.
In sum, two important questions for future research are: (i) how do we findthe point of a story, the conclusion for which it argues?; and (ii) why exactly
are some stories convincing and others not? I have tentatively answered thesequestions for simple fables in this article, but for parables things start getting
more complex, and full-length novels seem almost impossible to analyse thus.
This is not a problem that is exclusive to the formalisation of stories and storybased reasoning, however; much of the work in computational argumentation,whilst mathematically and formally sound, does sadly not transcend the basic
examples of flying penguins and Quaker presidents. When looked at from thisperspective, stories add a great deal to a more knowledge intensive and realistic
theory of argumentation.
A related question, one that is often presented with respect to stories inargumentation, is: why exactly should we use stories in formal argumentation?
Are they not simply a different and sometimes confusing way of representing
knowledge that can also be summarised as a simple sentence? Why should wetell the whole story when we can just use the argumentation scheme from section
4? Admittedly, stories are more interesting to read and more thought-provoking
than fairly dry, rule-based if . . . then . . . arguments. However, of what use is thisin situations aimed at automated reasoning? A software agent will not be moreeasily persuaded by a beautiful story than by a simple rule. And what about
the dangers of stories? We are all familiar with the idea that, for example incourt, a well-told story can trump a solid and strong argument. Summarising:are stories not just a rhetorical device, interesting to study when looking at
informal argument, rhetoric and human communication but of no direct use inartificial intelligence models?
In this regard, it is (again) instructive to consider the similarities between
reasoning with stories and reasoning with legal cases. Legal cases often have aso-called ratio decidendi, which consists of the rules of law or the reasons given
12

to justify a decision in a case. In a sense, the ratio decidenci can be viewed
as the point of a legal case: what does it mean to choose one decision overanother? As [7, 25] mention, there are essentially two camps in the debate as
to whether the ratio should be seen as being explicitly given (i.e. by an explicit
argumentation underlying the decision) or whether the ratio decidendi is implicit
and can be considered as flowing naturally from the facts of the decision andits outcome. We can also adhere to the second viewpoint when considering thepoints of stories: the point follows quite naturally from a coherent story and thehearer’s interpretation of it. A computational theory of human argumentation(or, more broadly, of human intelligence) needs a concept of stories and storybased reasoning because storytelling and understanding are central [28]. As an
intelligent person with an almost unmatchable capacity for absorbing and usinga wide variety of stories, I suspect that Trevor will agree with this and I lookforward to continuing our work for years to come.

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