1 / 23

Argumentative Story-based Analysis of Evidence

Argumentative Story-based Analysis of Evidence. Floris Bex (Law and ICT, U. Groningen) Henry Prakken (Law and ICT, U. Groningen / Information and Computing Sciences, U. Utrecht) Bart Verheij (Artificial Intelligence, U. Groningen). Contents.

wolfe
Download Presentation

Argumentative Story-based Analysis of Evidence

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Argumentative Story-based Analysis of Evidence Floris Bex (Law and ICT, U. Groningen) Henry Prakken (Law and ICT, U. Groningen / Information and Computing Sciences, U. Utrecht) Bart Verheij (Artificial Intelligence, U. Groningen)

  2. Contents • Evidential reasoning in legal theory/psychology • Stories (Pennington & Hastie, Crombag et al.) • Argument-graphs (Wigmore, Twining, Schum) • Evidential reasoning in AI (& Law) • Inference to the Best Explanation (Thagard) • Argumentation theory (Prakken, Walton, Gordon) • Combined theory • Example • Conclusions and future research

  3. Stories • Legal decisions are based on stories: • “sequences of events which form a meaningful whole” • Stories are compared and the “best” story is chosen

  4. Stories • Legal decisions are based on stories: • “sequences of events which form a meaningful whole” • Stories are compared and the “best” story is chosen • Problem: Relations between evidence, story and generalisations are unclear • Causal relations between events • Sources of evidence

  5. Argument structures • Structured argument-graphs from sources of evidence to conclusion (usually an event) • Generalisations are the “glue” 10 Event to be proven 9 Generalisation (inference warrant) 5 6 7 8 1 2 3 4 Sources of evidence

  6. Argument structures • Structured argument-graphs from sources of evidence to conclusion (usually an event) • Generalisations are the “glue” • Problem: sequence of events unclear • Passage of time • Causal relations between events

  7. Aims • Connect evidence to story using arguments • Formalise the combined theory in order to clarify the different relations story event event event event

  8. Reasoning with evidence in AI (& Law) • Two approaches: • Inference to the Best Explanation (IBE) • Form causal scenarios about “what happened” and compare these scenarios • Argumentation theory • Form arguments from premisses to conclusion

  9. the Rijkbloem case (1) • Nicole Lammers, a baker’s daughter had a relationship with Rijkbloem, a small-time criminal • After breaking up, Nicole and her parents go to Rijkbloem’s house to pick up some of her belongings • A fight develops, which ends in Mr. Lammer’s death

  10. the Rijkbloem case (2) • Fact: Mr. Lammers was shot through the head in Rijkbloem’s house • Prosecution’s story: • The fight between father and Rijkbloem started • Rijkbloem pulled out a gun • Rijkbloem shot father through the head • Father died

  11. the Rijkbloem case (3) • Fact: Mr. Lammers was shot through the head in Rijkbloem’s house • Defence’s story: • The fight between father and Rijkbloem started • Mrs. Lammers pulled a small gun out of her handbag and aimed the gun at Rijkbloem • Rijkbloem tried to push the gun away • The gun accidentally went off • Father was hit in the head and died

  12. IBE – causal reasoning • Stories involve causal reasoning • Stories are (at least) a sequence of events on a timeline • Events are supposedly caused by earlier events • Physical causation • Mental causation

  13. IBE - explanations • Given: • Causal rules T • Facts that need to be explained F • Hypothesise a set of causes H such that the H  T logically implies F (“explains F”) Rijkbloem shoots father Father is hit Father dies Rijkbloem pushes away gun gun goes off Mother pulls out gun

  14. IBE – choice • Choose between the different explanations:

  15. Arguments - evidential reasoning • Reasoning with sources of evidence is evidential • Witness W saying “P” is evidence for P • Gunpowder on Rijkbloem’s hands is evidence for Rijkbloem having fired a gun

  16. Arguments • (formal) argumentation theory Rijkbloem shot mr. Lammers If a witness says “P” then usually P Mrs. Lammers says ”Rijkbloem shot my husband!”

  17. Arguments - attacking • Attacking arguments Rijkbloem did not shoot mr. Lammers Rijkbloem shot mr. Lammers If a witness says “P” then usually P Rijkbloem says “I did not shoot mr. Lammers!” Mrs. Lammers says ”Rijkbloem shot my husband!”

  18. Arguments - attacking • Attacking arguments Rijkbloem shot mr. Lammers If a witness says “P” then usually P Mrs. Lammers is not trustworthy Mrs. Lammers says ”Rijkbloem shot my husband!”

  19. Combining the theories • The stories are modelled as explanations • Sources of evidence are connected to the stories using evidential arguments • Explanations are compared • How much additional evidence is explained? • How much additional evidence is contradicted? • Possible to reason about causal generalisations in the stories

  20. Combining the theoriesExample Rijkbloem shoots father Fight Father is hit Father dies Mrs. Lammers is not trustworthy Forensic report Mrs. Lammers’ testimony Police officer’s testimony

  21. Combining the theoriesExample Prosecutions story Defence’s story

  22. Conclusions • Stories and evidence have a seperate place in the theory • Stories and their supporting evidence can be easily combined • Better criteria for comparing stories

  23. Future work • Other criteria for comparing stories • Coherence • Plausibility

More Related