The Current Agenda of Argumentation Theory Douglas Walton: University of Windsor Assumption Chair in Argumentation Studies Distinguished Research Fellow of CRRAR Centre for Research in Reasoning, Argumentation & Rhetoric Talk at New University of Lisbon, February 10, 2010, 11:00 am, Room 1.05, Building I&D. Web page with pdf papers: http://dougwalton.ca
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The Current Agenda of Argumentation Theory Douglas Walton: University of Windsor Assumption Chair in Argumentation Studies Distinguished Research Fellow.
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The Current Agenda of Argumentation Theory
Douglas Walton: University of WindsorAssumption Chair in Argumentation StudiesDistinguished Research Fellow of CRRARCentre for Research in Reasoning, Argumentation & Rhetoric
Talk at New University of Lisbon, February 10, 2010, 11:00 am, Room 1.05, Building I&D.
Web page with pdf papers: http://dougwalton.ca
CRRAR and Assumption
CRRAR Mission Statement
The mission of the Centre for Research in Reasoning, Argumentation and Rhetoric is to be a national and international leader in individual and collaborative research into the theory and practice of reasoning, argument and argumentation, and rhetoric from the perspective of all related academic disciplines, and a leader in the application and dissemination of this research.
CRRAR is also the home of the journal Informal Logic. My position at CRRAR is that of Distinguished Research Fellow. I also hold the Chair of Argumentation Studies at Assumption
University, a college in the University of Windsor. Assumption was founded by the Basilian Fathers in 1870 as
part of Assumption University, which is now part of the University of Windsor.
What is an Argument?
An argument is a social and verbal means of trying to resolve, or at least contend with, a conflict or difference that has arisen between two parties engaged in a dialog by eliciting reasons on both sides (Walton, 2007).
According to this definition, an argument necessarily involves a claim that is advanced by one of the parties, typically a claim that the one party has put forward as true, and that the other
party questions. Arguments have premises and conclusions, they can be of
different kinds, they can be stronger or weaker (have weights), and different standards of proof can be required of them in different contexts of use.
Deductive Argument
Premise: Luigi is an Italian soccer player. Premise: All Italian soccer players are divers. Conclusion: Luigi is a diver. It is logically impossible for the premises to be true and the
conclusion false. But is the first premise true?
Inductive Argument
Premise: Luigi is an Italian soccer player. Premise: Most Italian soccer players are divers. Conclusion: Probably Luigi is a diver. It is improbable for the premises to be true and the conclusion
false.
Deductive, Inductive, and the 3rd Type: Abductive?
Wigmore (1931, p. 20) considered arguments of a kind that are commonly used in collecting evidence in law.
Last week the witness A had a quarrel with the defendant B, therefore A is probably biased against B. A was found with a bloody knife in B’s house, therefore A is probably the murderer of B.
Clue: Backward Reasoning by Explanation?
Defeasible Reasoning
Birds fly. Tweety is a bird. Therefore Tweety flies. Subject to exceptions (Tweety = penguin). Based on non-absolute generalizations. Nonmonotonic: valid arguments can become invalid by
adding premises.
Typical Argumentation Schemes
Common schemes include such familiar types of argumentation as argument from expert opinion, argument from lack of knowledge, argument from example, argument from a rule to a case, argument from a verbal classification, argument from position to know, argument from analogy, argument from precedent, argument from correlation to cause, practical reasoning, abductive reasoning, argument from gradualism, and the slippery slope argument.
Other schemes that have been studied include argument from waste (also called sunk costs argument), argument from temporal persistence and argument from appearance.
In addition to presumptive schemes, it is possible to treat deductive and inductive forms of argument as schemes.
All are linked arguments.
Deductive Linked Argument
Defeasible Linked Argument
Competence Center ELAN Fraunhofer FOKUS
The Carneades Model of Argument
Carneades models the structure of arguments the acceptability of statements burdens of proof (questioning, production and
persuasion) proof standards, such as preponderance of the
evidence Carneades is a
computational model: the functions of the model are all computable (i.e. recursive, decidable)
Carneades has an argument mapping tool with a graphical user interface: http://carneades.berlios.de/
Many Argumentation Support Tools
Scheuer, O., Loll, F., Pinkwart, N. & McLaren, B.M. (2010). Computer-Supported Argumentation: A Review of the State of the Art. International Journal of Computer-Supported Collaborative Learning. 5(1).
Two of them are Carneades and Araucaria. Rationale is another one that can be very useful for
philosophers.
Carneades (c.213 - c.128 B.C.)
Leader of the Academic Skeptics. Head of Plato’s (third) Academy. Developed a theory enabling human
action despite the lack of perfect knowledge, based on “reasonable grounds” and “probable” inferences.
Carneades’ notion of probability corresponds closely to what is now called defeasible, plausible, or nonmonotonic reasoning.
Competence Center ELAN Fraunhofer FOKUS
Linked Arguments
Competence Center ELAN Fraunhofer FOKUS
Convergent Arguments
Competence Center ELAN Fraunhofer FOKUS
Serial Arguments
Competence Center ELAN Fraunhofer FOKUS
Pros and Cons
Araucaria
Araucaria is a software tool for analyzing arguments. It aids a user in reconstructing and diagramming an argument using a simple point-and-click interface. The software also supports argumentation schemes, and provides a user-customizable set of schemes with which to analyze arguments.
Once arguments have been analyzed they can be saved in a portable format called AML, the Argument Markup Language.
Major Premise: Source E is an expert in domain D containing proposition A.
Minor Premise: E asserts that proposition A (in domain D) is true (false).
Conclusion: A may plausibly be taken to be true (false).
Application to Law Currently one of the most active areas of application is to law. Researchers in AI and Law are prominent users of
argumentation tools, including Tom Gordon, Bart Verheij, Henry Prakken, Trevor Bench Capon and Floris Bex.
Scheme from Expert Opinion
Corroborative Expert Opinions:Linked and Convergent Arguments
Six Critical Questions
Expertise Question: How knowledgeable is E as an expert source?
Field Question: Is E an expert in the field D that A is in? Opinion Question: What did E assert that implies A? Trustworthiness Question: Is E personally reliable as a source? Consistency Question: Is A consistent with what other experts
assert? Backup Evidence Question: Is E’s assertion based on evidence?
Legal Expert Opinion Scheme
Competence Premise (Ordinary Premise): E is an expert in knowledge domain D.
Statement Premise (Ordinary Premise): E said the sentence S*. Interpretation Premise (Ordinary Premise): S is a reasonable
interpretation of S*. Domain Premise (Assumption): S is in D. Depth of Knowledge Premise (Assumption): The knowledge of E
about D is deep enough to know about S. Careful Analysis Premise (Assumption 3): E’s testimony S* is
based on his own careful analysis of evidence in this case. Other Experts Premise (Exception): S is inconsistent with what
other experts in D say. Credibility Premise (Exception): E is not credible. Conclusion: S may plausibly be taken to be true.
Scheme for Practical Reasoning
Major Premise: I have a goal G. Minor Premise: Carrying out this action A is a means to realize
G. Conclusion: Therefore, I ought (practically speaking) to carry
out this action A.
Critical Questions for Scheme
CQ1: What other goals do I have that should be considered that might conflict with G?
CQ2: What alternative actions to my bringing about A that would also bring about G should be considered?
CQ3: Among bringing about A and these alternative actions, which is arguably the most efficient?
CQ4: What grounds are there for arguing that it is practically possible for me to bring about A?
CQ5: What consequences of my bringing about A should also be taken into account?
Lunesta Sleep Medication Ad
The picture in the ad shows the head and shoulders of a young man asleep, his head resting against the pillow.
In large print above the picture, the words “The sleep you’ve been dreaming of.” are printed.
Below the picture it says, “Soothing Rest for Mind and Body.” Below that, the text of the ad appears [as quoted]. “It’s what you’ve been craving. Peaceful sleep without a
struggle. That’s what Lunesta is all about: helping most people fall asleep quickly, and stay asleep all through the night”.
Premises of Lunesta Argument
Premise: my goal is to have peaceful sleep without a struggle. Premise: taking Lunesta is the best means to have peaceful
sleep without a struggle. Premise: Lunesta helps most people fall asleep quickly. Premise: they stay asleep all through the night.
Argument Map of Lunesta Ad
Enthymemes
An enthymeme is an argument with an implicit premise or conclusion.
All physicians are college graduates, so all members of the AMA are college graduates.
MISSING PREMISE: All members of the AMA are physicians. Roadside sign: “The bigger the burger, the better the burger.
The burgers are bigger at Burger King.” MISSING CONCLUSION: The burgers are better at Burger King. In the Lunesta ad, the conclusion is also implicit.
Normative Models of Dialog
Arguments are taken in traditional logic, to consist of a set of premises (statements) and a conclusion (another statement).
The dialog is a model represents the conversational setting in which an argument was put forward for some purpose.
There are different types of dialog. Each dialog has an opening stage, and argumentation stage
and a closing stage.
Classification of Dialogs
Dialog
PersuasionInformation
SeekingNegotiation
Critical Discussion
InterviewAdvice
Solicitation
Expert Consultation
Inquiry
Scientific Inquiry
Public Inquiry
Deliberation Eristic
Quarrel
TYPE OF DIALOG
INITIAL SITUATION
PARTICIPANT’S GOAL
GOAL OF DIALOG
Persuasion Conflict of Opinions
Persuade Other Party
Resolve or Clarify Issue
Inquiry Need to Have Proof
Find and Verify Evidence
Prove (Disprove) Hypothesis
Negotiation Conflict of Interests
Get What You Most Want
Reasonable Settlement that Both Can Live With
Information-Seeking
Need Information
Acquire or Give Information
Exchange Information
Deliberation Dilemma or Practical Choice
Co-ordinate Goals and Actions
Decide Best Available Course of Action
Eristic Personal Conflict
Verbally Hit Out at Opponent
Reveal Deeper Basis of Conflict
Types of Dialog
Dialogue Structure
Salmon’s Case
Salmon sold medicines in London. M’Kensie bought from him some pills for rheumatism; after numerous doses he died. The medical men, on a postmortem examination, affirmed that certain ingredients of these pills had caused his death; and Salmon was indicted for manslaughter. But on the trial he produced many witnesses, who had taken the same kind of pills with much benefit; one witness affirmed that he had taken twenty thousand of them within the past two years, to his great benefit! If these circumstances were true, the inference was inevitable that the pills were not lethal. But was the testimony to this circumstance true?
Key List of Statements in Salmon’s Case
(A) The medical man affirmed that certain ingredients of the pills had caused M’s death.
(B) The medical man is an expert in medicine [implicit premise].(C) Certain ingredients in the pills had caused M’s death.(D) M’s taking the pills caused his death.(E) Witness W testified that he took the same kind of pills and
they caused him no harm.(F) Witness W is in a position to know about the effects of the pills
on him [implicit premise].(G) If the pills caused no harm to W, the pills were not lethal
[implicit premise]. (H) The pills were not lethal.
Diagram of Salmon Case
How Arguments are Evaluated
Burdens of proof and standards of proof, along with argument weights, determine how to evaluate the argumentation in a dialog.
The burden and standard of proof are set at the opening stage, and depend on the type of dialog.
In the argumentation stage, each side presents reasons supporting its view and attacks the opposed view by raising critical questions and rebuttals.
The burdens and standards are then applied at the closing
stage to determine which side won and which lost the dialog.
Defining Burden of Proof
Burden of proof has three components: (a) a contained proposition representing one arguer’s claim to be proved (b) which arguer (proponent or respondent) has that thesis, and (c) a standard of proof required for proving that thesis.
There are different types of burden of proof recognized in law.
Two Burdens of Proof in Law
Burden of Persuasion (also called legal burden of proof): in a murder trial, the prosecution must prove the charge that the defendant committed murder.
Evidential Burden (also called burden of production): if a person accused of burglary is found carrying “burglarious implements”, an evidential burden is placed on him to give some explanation of why he had such articles in his possession. If he fails to do so, the conclusion can be drawn he was
carrying them to commit burglary.
Standards of Proof (Gordon & Walton, 2009)
The standard of scintilla of evidence iff there is one argument supporting the claim.
The preponderance of the evidence standard is met iff scintilla of evidence standard is met and the weight of evidence for the claim is greater than the weight against it.
The clear and convincing evidence standard is met iff the preponderance of the evidence standard is met and the weight of the pro arguments exceeds that of the con arguments by some specified threshold.
The beyond reasonable doubt standard is met iff the clear and convincing evidence standard is met and the weight of the con arguments is below some specified threshold.
These standards are defined in the Carneades model.
Locutions and Speech Acts
Statements and questions are locutions. Making an assertion is a speech act. Asking a question is a speech act. Asking for an explanation is an even more specific speech act. Putting forward an argument is a speech act. Offering an explanation is a speech act.
Speech Act Moves in a Dialogue
Goal of D ialogue
Respondent's Move
Proponent's Move
Sequenc e of Moves
Post-c ondition
Initial S ituation
Turn-taking
Speec h Ac t
Pre-c ondition
Speec h Ac t
Dialogue Models of Explanation
The dialogue model is not restricted only to argumentation. An explanation can be modeled as a dialogue between two
agents in which one agent is presumed by a second agent to understand something, and the second agent asks a question meant to enable him to come to understand it as well.
The dialectical model articulates the view of Scriven (2002, p. 49): “Explanation is literally and logically the process of filling in gaps in understanding, and to do this we must start out with some understanding of something.”
Argument or Explanation?
Test to judge whether a given text of discourse contains an argument or an explanation.
Take the statement that is the thing to be proved or explained, and ask yourself the following question. Is it taken as an accepted fact, or something that is in doubt? If the former, it’s an explanation. If the latter, it’s an argument.
The Goal of Dialogue is Different The purpose of an argument is to get the hearer to come to
accept something that is doubtful or unsettled. The purpose of an explanation is to get him to understand something that he already accepts as a fact.
Conditions in the Dialogue Model
Dialogue Conditions: explainee asks question of a specific form asking about what is assumed to be a known fact S.
Understanding Conditions: explainee does not understand S, but assumes that explainer understands S.
Success Conditions: explainer by what she says brings the explainee to understand S.
Rules for Explan Dialogue System
Opening: when explainee makes an explanation request for S (accepted fact).
Locution Rules: defines different speech acts (kinds of moves) that are allowed.
Dialogue Rules: show which move must follow each previous kind of move.
Success Rules: show when transfer of understanding has been achieved.
Closing1: when explainee says ‘In understand it’. Closing2: explainee shows understanding through
testing.
Explanation in a Sequence of Dialogue
Event Taken as Factual by Both Parties
Something Perplexing to Respondent about Event
Respondent asks Proponent for Help in Understanding
Proponent Offers Explanation Attempt
Attempt Judged to be Successful or not by Respondent