Arguing with Stories
Floris Bex1 and Trevor Bench-Capon2
1

Department of Humanities Computing, University of Groningen. The Netherlands
2
Department of Computer Science, University of Liverpool, UKAbstract. Stories can be powerful argumentative vehicles, and they are often
used in arguments from analogy, most notably as parables or allegories wherethe story illustrates an important claim of the argument. Case Based Reasoningin Law has many similar features. In this article, we want to take a further stepat computationally modelling the connection between stories and argumentationin analogical reasoning.
Keywords: Argumentation, Stories, Analogy

1Introduction

Stories can be powerful argumentative vehicles: we often persuade not by
imparting simple facts and rules, but rather by providing an interesting andconvincing narrative. Stories are particularly useful for persuading people bychanging attitudes, as in the New Testament parables, or for reinforcing attitudes, whereby the stories illustrate various group cultural norms. Many folktales are of this type, as are many children’s stories.
Stories can play an important role in legal argumentation, where one objective
is to determine the facts of a case. It is, for example, possible to argue for thetruth of a story about “what happened” in a case using evidence, and this story
can then be used to argue that a particular legal consequence should hold. For
example, if we can prove using evidence that Bob drove to Wilma’s house tohurt her because she was seeing another man, and that subsequently Bob
killed Wilma, we can conclude from this story that Bob committed murder.
This combination of stories and arguments has been discussed in recent workon computational argumentation [3][4].
Stories are also often used in arguments from analogy, most notably as parables or allegories where the story illustrates an important claim of the argument. For example, the above-mentioned parables or Plato’s allegories arestories which are meant to persuade us of certain ideas by appealing to, orCMNA 2013

challenging, our core beliefs and values. Similarly, thought experiments like
Searle’s Chinese Room, intended to direct the inutitions of their audience areoften also presented as a small anecdote or story.
Analogical reasoning, where two stories or cases are compared, has been investigated formally in the field of Case-based Reasoning [5], and ideas fromthis early work were later on used in approaches to legal CBR (e.g. CATO[1]), which adds argument moves to explore the similarities and differences
between legal cases. Recently, we have shown how these argument moves canbe applied to non-legal cases (i.e. stories) and how story schemes – genericscripts about how things tend to happen – can be used in this argumentation
about similarities [2]. However, it was not fully explained how these stories
can be used in a broader argument: that is, why similarities between stories
can be persuasive.
In this article, we want to take a further step at modelling the connection between stories and argumentation in analogical reasoning. Section 2 briefly
shows how arguments from analogy can be based on stories, and provides ashort but illustrative example. Section 3 then discusses some of the objections
and difficulties of integrating stories and arguments.

2Arguments from Analogy

Stories are often used in arguments from analogy. The basic scheme for thistype of argument is as follows [10].
Similarity Premise: Generally, case C1 is similar to case C2.
Base Premise: A is true (false) in case C1.
Conclusion: A is true (false) in case C2.

The critical questions that are given for this basic scheme are as follows.
CQ1: Are there respects in which C1 and C2 are different that would tend to undermine the force of the similarity cited?
CQ2: Is A the right conclusion to be drawn in C1?
CQ3: Is there some other case C3 that is also similar to C1, but in which some conclusion other than A should be drawn?

2.1

Story Similarity

The similarity premise and the first critical question are about whether case C1
and C2 are similar (enough) for a comparison to be drawn. In [2] a model ofstory similarity is presented: stories are specific sequences of events and story
schemes are general scenarios consisting of story roles, general roles that elements of a story can fulfil. Stories can be matched to schemes by assigning
the facts to their respective roles. Two cases are thus said to be similar if they
can be matched to the same story scheme. This is similar to matching two
specific cases directly (i.e. without an intermediate story scheme, as in [5]),but a scheme allows us to match two similar cases C1 and C2 even if not every
element of C1 maps to an element of C2 (as long as the elements of C1 and C2
match a story role in the scheme). Note that there are also analogies which do
not depend on similarity: in some cases the elements of one story are symbolic for another (e.g. a pen symbolises an author) [6].
As an example of matching two stories, consider the story in Searle’s Chinese
Room Argument [9]: there is a man in a room – a Chinese character x is
passed to the man– the man looks up x in a book which for each character
gives a corresponding meaningful character – the man presents the corresponding character y to the outside. Using story schemes, we can say that theChinese room story can be matched to the following story scheme: enclosed
processor – pass language unit to processor – lookup language unit and findcorresponding language unit – pass corresponding language unit to outside.
The point is that, even though the “Room as a whole” might (and, it can beassumed, does) pass the Turing test, the man clearly does not understand Chinese. Searle makes this point to then draw the analogy from the Chinese
Room to a computer: if you give a Chinese character, or any language unit forthat matter, to a computer all it does is perform a lookup operation without
understanding the language. It is thus possible to compare a story about a manin a room and a computer by matching both stories to the above scheme.
Legal Case-based Reasoning such as [1] takes a similar approach to [5], but
makes the identification of relevant similarities and differences between legal
cases the subject of argumentation. In [2], the focus is on factual stories,
which are very similar to legal cases in that both stories and cases present a
coherent set of facts. A difference is that in legal cases the elements of thecase (factors) are somehow legally relevant, whilst this is not a requirementfor stories. Furthermore, elements of time and causality do not feature explicitly in the cases described as sets of factors in [1], whilst these are central tostories. However, despite these differences it is still possible to use the argumentative moves of [1] to explore similarities between stories. For example,
one can pose another story as a counterargument to the original story-basedargument (see CQ3). In case of the Chinese Room, one is reminded of theoriginal Mechanical Turk, a chess playing automaton in the 18th century. Everyone thought the machine was intelligent until it was revealed to have humanoperator hidden within it. With this story we can argue that intelligence ispossible for a machine: no-one disputes the intelligence of the operator of theTurk. While Searle’s story shows that we might be misled into thinking mechanical behaviour to be intelligent, the Turk shows that we can still conceiveof machines behaving in a way that we would wish to call intelligent.
It is possible for the original story to be told in such a way that possible future
critical questions of the type CQ3 are pre-empted.
This can be seen in a Parable like the Good Samaritan, which Jesus tells toprovide an answer to the question who is my neighbour? In the course of thestory, some expected answers (my co-religionists, my countryman) are mooted and dismissed as the priest and Levite pass by on the other side, before thecorrect answer any human being who shows compassion – even my religious
and national enemy – is provided in the person of the Samaritan. In this way
two of the possible responses which might have led to CQ3 are proposed anddismissed, so there is no opportunity to counter with the story of the GoodPriest.
2.2

Drawing Conclusions from Stories

The work in [2] mainly focuses on arguments about stories: arguments areused to reason about the similarity of multiple stories. However, it is also possible to use a story as an argument, that is, propose a story as a reason forsome conclusion. This conclusion is referenced to as A in the Base Premise,
the Conclusion and CQ2 of the scheme for argument from analogy. So here
we have both reasoning about and with stories: first we infer that story C2 issimilar to story C1 from which previously conclusion A was inferred (reasoning about stories, left side of Figure 1). This then allows us to infer A from C2(reasoning with stories, right side of Figure 1).

A

conclusion

conclusion

argument

story C1

A

argument

similarstory C2

story C2

Figure 1: Drawing the same conclusion from a similar story

The question is how to draw a conclusion from a particular story. In legal
CBR, there are legal rules and principles that allow us to infer the conclusionfrom the factors in a case [7]. For stories, we need to look at their point. Thispoint can be explicit when it is mentioned in the text of the story, or when thestory is told in a dialogue. For example, the Good Samaritan was told in response to a question: the point is then the answer to this question, and answering the question with a story gives rise to an inferential relation between thestory and its point. In other cases, it is left up to the reader to infer the point
based on their cultural values and beliefs. For example, most people automatically understand the point the fable “the Tortoise and the Hare” to be something like “the more haste, the less speed”.
Often the point has to do with a “twist in the tale”, which adds persuasivenessto the story. So in Searle’s story the system is satisfying the Turing test but
then he reveals that there is no intelligence being engaged even with a humaninside. In the case of the Good Samaritan the man is helped by one of whom
we would least expect it, an enemy. As explained above the twist reveals thedesired conclusion after alternative, more expected, conclusions have beenraised and rejected, so that CQ3 can be pre-empted.

3Conclusion

In this paper we have tried to demonstrate the next steps towards a fully integrated account of argument and narrative. We have shown what the role ofstories is in argument from analogy, and how such arguments (and their critical questions) can be formally modelled using familiar techniques from CBR.
Argument from analogy preys on the temptation to generalise from limited
experience which seems ever present in people, often leading people to state
fallacious generalisations. (“Whenever I take an umbrella it does not rain.”).
In its standard form the argument from analogy is very plain. But stories cangive the analogy more substance and hence more persuasiveness. Also notethat often it is not the truth of a story that is at issue; for example Wittgensteinargued that “Christianity is not based on truth; rather, it offers us a narrativeand says: now, believe!” [11]. A compelling argument does not necessarily
have to be true, especially when it appeals to values (as parables often do).
There remain a large number of open questions regarding the interactions
between narrative and argument. For example, how exactly can we derive thepoint of a story from the story and the context in which it is told? How dodifferent types of stories change or reinforce attitudes? Are stories just a rhetorical “trick” or can they be used to express information that otherwise remains implicit? Providing formal answers to these and other questions is pertinent if we want to fully integrate stories and arguments.

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