Posts Tagged ‘argumentation’

Evidence Informatics

January 20th, 2015

I sent off my revised abstract to ECA Lisbon 2015, the European Conference on Argumentation. Evidence informatics, in 75 words:

Reasoning and decision-making are common throughout human activity. Increasingly, human reasoning is mediated by information technology, either to support collective action at a distance, or to support individual decision-making and sense-making.

We will describe the nascent field of “evidence informatics”, which considers how to structure reasoning and evidence. Comparing and contrasting evidence support tools in different disciplines will help determine reusable underlying principles, shared between fields such as legal informatics, evidence-based policy, and cognitive ergonomics.

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Four types of evidence

May 17th, 2013

A great image “Four types of evidence” appears in a recent paper on probabalistic argumentation schemes1. The delineation of 4 types of evidence2 serves the larger goal of the paper — which is to describe how to combine evidence of different types.

Four Types of Evidence, from Tang et al. ArgMAS2013
Four Types of Evidence, from Tang et al. ArgMAS2013

The four types of evidence depicted are:

  1. Consonant Evidence – each set is wholly contained in another (all sets can be arranged in a nested series of subsets)
  2. Consistent Evidence – have a common element (nonempty intersection of all sets)
  3. Disjoint Evidence – in which there is no overlap (pairwise disjoint intersection of sets)
  4. Arbitrary Evidence – where none of the three preceding situations holds (i.e. there is no consensus but some agreement)

Evidence classification could possibly be thought of in conjunction with argument classification; for the latter, see my earlier musings Towards a Catalog of Argumentation Patterns.

  1. Dempster-Shafer Argument Schemes‘ by Yuqing TangNir OrenSimon Parsons, and Katia Sycara (2013) in Proceedings of ArgMAS 2013. []
  2. These, the authors mention, were drawn from an earlier technical report: K. Stentz and S. Ferson. Combination of evidence in Dempster-Shafer theory. Technical Report SAND 2002-0835, Sandia National Laboratories, 2002. See especially pages 10-13. The context in that technical report, is sensor fusion using Dempster-Shafer Theory, which as I have since learned, is a common approach to combination of evidence. []

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Towards a Catalog of Argumentation Patterns

November 16th, 2012

Argumentation analysis can be simplified by thinking about the patterns used.
But what are the key patterns? Here are two diagrams showing different views.

Rahwan suggests 5 common basic argument structures: single, linked, convergent, serial, and divergent.1

Iyad Rahwan. Mass argumentation and the Semantic Web. 2008.

Meanwhile, Wei and Praken give 5 possible argumentative structures that have one or two inferences.2

From Bin Wei and Henry Prakken. Defining the structure of arguments with AI models of argumentation.

Why 5 structures? Five connected structures emerge from having two types of inference — as unit I (single) and unit II (linked) inference. With two inferences of either type, we can make five patterns:3

(1) unit I argument (single)
(2) unit II argument (linked)
(3) multiple unit I argument (serial)
(4) multiple unit II argument
(5) mixed argument

What is interesting is to look at the differences: Rahwen doesn’t cover (4) multiple unit II and (5) mixed arguments. Meanwhile, Wei and Prakken’s list doesn’t include Rahwen’s convergent & divergent argumentation.

So which are the key patterns?

Single and linked arguments are fundamental, and serial arguments are mathematically simple and Rahwen suggests that they are common in use.4But the rest?

Convergent & divergent argumentation structures are both candidates: Wei and Prakken don’t cover these, I suspect, since each could be separated into two separate single arguments, which have the same premise (divergent) or conclusion (convergent). These structures can be important in practice: Convergent arguments give multiple reasons for coming to a conclusion — essential when no single reason suffices. The structure of divergent arguments seems to me to be most useful for showing contradictions in diverse conclusions, e.g. for reductio ad absurdum arguments; I’d love a real-world example of a divergent argument where keeping this structure is important.

  1. Iyad Rahwan. Mass argumentation and the Semantic Web. Web Semantics: Science, Services and Agents on the World Wide Web, 6(1):29–37, February 2008. http://dx.doi.org/10.1016/j.websem.2007.11.007 []
  2. Bin Wei and Henry Prakken. Defining the structure of arguments with AI models of argumentation. Computational Models of Natural Argument XII at ECAI 2012. Pages 60-64 in Proceedings. []
  3. Definition 9. The types of arguments can be defined as follows:
    (1) An argument A is a unit I argument iff A has the form B ⇒ ψ and subargument B is an atomic argument B : φ. We call the inference rule φ ⇒ ψ a unit I inference.
    (2) An argument A is a unit II argument iff A has the form B1,…,Bn ⇒ ψ and subarguments A : B1,…,Bn are atomic arguments B1 : φ1 ,. . . ,Bn : φn . We call the inference rule φ1,…,φn ⇒ ψ a unit II inference.
    (3) An argument A is a multiple unit I argument iff all inferences r1, . . . , rn in the argument A are unit I inferences.
    (4) An argument A is a multiple unit II argument iff all inferences r1, . . . , rn in the argument A are unit II inferences.
    (5) An argument A is a mixed argument iff A has at least one unit I subargument and unit II subargument.
    We display the diagrams of argument types in Figure 3. For simplicity, we assume n = 2 in these diagrams and show only one case of a mixed argument. []
  4. Statistics on argument use would be valuable, but we have limited information about this. Aracuaria DB? Output from argumentation mining? []

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Argumentation on Twitter

November 19th, 2011

Here’s an argument made on Twitter:

Difference between cakes and biscuits? When stale, cakes go hard, biscuits go soft. Hence Jaffa Cakes are cakes. (Was official EU ruling).

I just love this example:

  1. First, you can find it with “hence” (see cue phrases from an appendix to Marcu‘s thesis).
  2. Second, the notion of this EU (tax) ruling amuses me.
  3. Third, it shows that 140 characters is enough for a complex argumentative structure. This has three main claims: When stale, cakes go hard, biscuits go soft; Jaffa Cakes are cakes; and [Jaffa Cakes are cakes due to] official EU ruling.
  4. Enthymemes anyone?

It’s hard, though, to draw the line between an argument and an explanation in this context.
Jaffa Cakes, for you North American readers, are a common dessert-y snack in Ireland and the UK. Vaguely like Kandy Kakes found in the Philadelphia area/East Coast, but usually have an orange filling.

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“Like” and its misuse

October 20th, 2010

Language evolves, and we use words loosely. But I’m more and more disturbed with the way “Like” is being manhandled.
A misuse of the Like button
Argumentation will need to encompass polarity; so I hope that it can help.

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