One of the advantages of formal argumentation theory as a way of defining nonmonotonic inference ... more One of the advantages of formal argumentation theory as a way of defining nonmonotonic inference is that it applies concepts that are close to human reasoning, like arguments and discussion. In recent years, various discussion games for formal argumentation have been stated [2]. The idea is that these discussion games can be used as proof procedures for the different argumentation semantics. That is, an argument is accepted with respect to a particular semantics iff it is possible to win the associated discussion game.2 This makes it possible to use the discussion games for the purpose of explanation. Instead of simply mentioning that an argument is in, say, the grounded extension, the computer can allow the user to raise objections (counter arguments) and address these (using counter counter arguments) after which the user is again allowed to raise objections, etc. The aim is that at some moment, all the user’s potential objections have been uttered and addressed, and that the user is ready to accept the argument the discussion started with. Our current demonstrator DISCO3 (DIscussion COmputation) provides a web-based implementation of the Preferred Game [3] and of the Grounded Discussion Game [1].4 The demonstrator is based entirely on Javascript, and all computation is performed at client side. On starting, the user can either open an existing argumentation framework (which uses a JSON based file format) or construct one manually by adding arguments and attacks to an initially empty canvas. Once the argumentation framework has been defined, the user can play either the preferred game or the grounded discussion game.
Edmond Awad, The Media Lab, Massachusetts Institute of Technology, USA; Masdar Institute, UAE Jea... more Edmond Awad, The Media Lab, Massachusetts Institute of Technology, USA; Masdar Institute, UAE Jean-François Bonnefon, Center for Research in Management, Toulouse School of Economics, France Martin Caminada, School of Computer Science & Informatics, Cardiff University, UK Thomas Malone, Sloan School of Management, Massachusetts Institute of Technology, USA Iyad Rahwan, The Media Lab, Massachusetts Institute of Technology, USA; Masdar Institute, UAE
Given an argumentation framework and a group of agents, the individuals may have divergent opinio... more Given an argumentation framework and a group of agents, the individuals may have divergent opinions on the status of the arguments. If the group needs to reach a common position on the argumentation framework, the question is how the individual evaluations can be mapped into a collective one. This problem has been recently investigated in [1]. In this paper, we study under which conditions these operators are Pareto optimal and whether they are manipulable.
The concept of strong admissibility plays an important rolein some of the dialectical proof proce... more The concept of strong admissibility plays an important rolein some of the dialectical proof procedures that have been stated forgrounded semantics. As the grounded extension is the (unique) biggeststrongly admissible set, to show that an argument is in the groundedextension it suffices to show that it is in a strongly admissible set. Weare interested in identifying a strongly admissible set that minimizes thenumber of steps needed in the associated dialectical proof procedure. Inthe current work, we look at the computational complexity of doing so.
An often mentioned advantage of argumentation theory (compared to other formalisms for non-monoto... more An often mentioned advantage of argumentation theory (compared to other formalisms for non-monotonic reasoning) is that it is based on concepts of human reasoning. However, quite some of the argumentation semantics are defined in terms of fixpoints [1] which, although appealing to mathematicians, do not seem to coincide with how most humans tend to reason in everyday life. In order to bring argument-based entailment closer to human intuitions, we propose to use formal discussion as a bridge technology. For this, we are applying argumentbased discussion theory [3] which reformulates argument-based reasoning as the ability to win a particular type of discussion. More specifically, an argument is in the grounded extension iff a proponent of the argument has a winning strategy in the Grounded Discussion Game [3]. In the context of abstract argumentation theory, an implementation of the Grounded Discussion Game (as well as of the Preferred Discussion Game) is already available [2]. With ...
The current book chapter examines how to apply Dung’s theory of abstract argumentation to define ... more The current book chapter examines how to apply Dung’s theory of abstract argumentation to define meaningful forms of nonmonotonic inference. The idea is that arguments are constructed using strict and defeasible inference rules, and that it is then examined how these arguments attack (or defeat) each other. The thus defined argumentation framework provides the basis for applying Dung-style semantics, yielding a number of extensions of arguments. As each of the constructed arguments has a conclusion, an extension of arguments has an associated extension of conclusions. It are these extensions of conclusions that we are interested in. In particular, we ask ourselves whether each of these extensions is (1) consistent, (2) closed under the strict inference rules and (3) free from undesired interference. We examine the current generation of techniques to satisfy these properties, and identify some research issues that are yet to be dealt with.
In the current chapter, we interpret a number of mainstream argumentation semantics by means of s... more In the current chapter, we interpret a number of mainstream argumentation semantics by means of structured discussion. The idea is that an argument is justified according to a particular argumentation semantics iff it is possible to win a discussion of a particular type. Hence, different argumentation semantics correspond to different types of discussion. Our aim is to provide an overview of what these discussions look like, and their formal correspondence to argumentation semantics.
On the Web, there is always a need to aggregate opinions from the crowd (as in posts, social netw... more On the Web, there is always a need to aggregate opinions from the crowd (as in posts, social networks, forums, etc.). Different mechanisms have been implemented to capture these opinions such as Like in Facebook, Favorite in Twitter, thumbs-up/-down, flagging, and so on. However, in more contested domains (e.g., Wikipedia, political discussion, and climate change discussion), these mechanisms are not sufficient, since they only deal with each issue independently without considering the relationships between different claims. We can view a set of conflicting arguments as a graph in which the nodes represent arguments and the arcs between these nodes represent the defeat relation. A group of people can then collectively evaluate such graphs. To do this, the group must use a rule to aggregate their individual opinions about the entire argument graph. Here we present the first experimental evaluation of different principles commonly employed by aggregation rules presented in the literat...
One of the advantages of formal argumentation theory as a way of defining nonmonotonic inference ... more One of the advantages of formal argumentation theory as a way of defining nonmonotonic inference is that it applies concepts that are close to human reasoning, like arguments and discussion. In recent years, various discussion games for formal argumentation have been stated [2]. The idea is that these discussion games can be used as proof procedures for the different argumentation semantics. That is, an argument is accepted with respect to a particular semantics iff it is possible to win the associated discussion game.2 This makes it possible to use the discussion games for the purpose of explanation. Instead of simply mentioning that an argument is in, say, the grounded extension, the computer can allow the user to raise objections (counter arguments) and address these (using counter counter arguments) after which the user is again allowed to raise objections, etc. The aim is that at some moment, all the user’s potential objections have been uttered and addressed, and that the user is ready to accept the argument the discussion started with. Our current demonstrator DISCO3 (DIscussion COmputation) provides a web-based implementation of the Preferred Game [3] and of the Grounded Discussion Game [1].4 The demonstrator is based entirely on Javascript, and all computation is performed at client side. On starting, the user can either open an existing argumentation framework (which uses a JSON based file format) or construct one manually by adding arguments and attacks to an initially empty canvas. Once the argumentation framework has been defined, the user can play either the preferred game or the grounded discussion game.
Edmond Awad, The Media Lab, Massachusetts Institute of Technology, USA; Masdar Institute, UAE Jea... more Edmond Awad, The Media Lab, Massachusetts Institute of Technology, USA; Masdar Institute, UAE Jean-François Bonnefon, Center for Research in Management, Toulouse School of Economics, France Martin Caminada, School of Computer Science & Informatics, Cardiff University, UK Thomas Malone, Sloan School of Management, Massachusetts Institute of Technology, USA Iyad Rahwan, The Media Lab, Massachusetts Institute of Technology, USA; Masdar Institute, UAE
Given an argumentation framework and a group of agents, the individuals may have divergent opinio... more Given an argumentation framework and a group of agents, the individuals may have divergent opinions on the status of the arguments. If the group needs to reach a common position on the argumentation framework, the question is how the individual evaluations can be mapped into a collective one. This problem has been recently investigated in [1]. In this paper, we study under which conditions these operators are Pareto optimal and whether they are manipulable.
The concept of strong admissibility plays an important rolein some of the dialectical proof proce... more The concept of strong admissibility plays an important rolein some of the dialectical proof procedures that have been stated forgrounded semantics. As the grounded extension is the (unique) biggeststrongly admissible set, to show that an argument is in the groundedextension it suffices to show that it is in a strongly admissible set. Weare interested in identifying a strongly admissible set that minimizes thenumber of steps needed in the associated dialectical proof procedure. Inthe current work, we look at the computational complexity of doing so.
An often mentioned advantage of argumentation theory (compared to other formalisms for non-monoto... more An often mentioned advantage of argumentation theory (compared to other formalisms for non-monotonic reasoning) is that it is based on concepts of human reasoning. However, quite some of the argumentation semantics are defined in terms of fixpoints [1] which, although appealing to mathematicians, do not seem to coincide with how most humans tend to reason in everyday life. In order to bring argument-based entailment closer to human intuitions, we propose to use formal discussion as a bridge technology. For this, we are applying argumentbased discussion theory [3] which reformulates argument-based reasoning as the ability to win a particular type of discussion. More specifically, an argument is in the grounded extension iff a proponent of the argument has a winning strategy in the Grounded Discussion Game [3]. In the context of abstract argumentation theory, an implementation of the Grounded Discussion Game (as well as of the Preferred Discussion Game) is already available [2]. With ...
The current book chapter examines how to apply Dung’s theory of abstract argumentation to define ... more The current book chapter examines how to apply Dung’s theory of abstract argumentation to define meaningful forms of nonmonotonic inference. The idea is that arguments are constructed using strict and defeasible inference rules, and that it is then examined how these arguments attack (or defeat) each other. The thus defined argumentation framework provides the basis for applying Dung-style semantics, yielding a number of extensions of arguments. As each of the constructed arguments has a conclusion, an extension of arguments has an associated extension of conclusions. It are these extensions of conclusions that we are interested in. In particular, we ask ourselves whether each of these extensions is (1) consistent, (2) closed under the strict inference rules and (3) free from undesired interference. We examine the current generation of techniques to satisfy these properties, and identify some research issues that are yet to be dealt with.
In the current chapter, we interpret a number of mainstream argumentation semantics by means of s... more In the current chapter, we interpret a number of mainstream argumentation semantics by means of structured discussion. The idea is that an argument is justified according to a particular argumentation semantics iff it is possible to win a discussion of a particular type. Hence, different argumentation semantics correspond to different types of discussion. Our aim is to provide an overview of what these discussions look like, and their formal correspondence to argumentation semantics.
On the Web, there is always a need to aggregate opinions from the crowd (as in posts, social netw... more On the Web, there is always a need to aggregate opinions from the crowd (as in posts, social networks, forums, etc.). Different mechanisms have been implemented to capture these opinions such as Like in Facebook, Favorite in Twitter, thumbs-up/-down, flagging, and so on. However, in more contested domains (e.g., Wikipedia, political discussion, and climate change discussion), these mechanisms are not sufficient, since they only deal with each issue independently without considering the relationships between different claims. We can view a set of conflicting arguments as a graph in which the nodes represent arguments and the arcs between these nodes represent the defeat relation. A group of people can then collectively evaluate such graphs. To do this, the group must use a rule to aggregate their individual opinions about the entire argument graph. Here we present the first experimental evaluation of different principles commonly employed by aggregation rules presented in the literat...
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