《LOGICAL TOOLS FOR MODELLING LEGAL ARGUMENT A STUDY OF DEFEASIBLE REASONING IN LAW》求取 ⇩

1 INTRODUCTION1

1.1 AI, Logic and Legal Reasoning: Some General Remarks1

1.1.1 An Overview1

1.1.2 Artificial Intelligence2

1.1.3 Computable Aspects of Legal Reasoning5

1.1.4 The Role of Logic6

1.2 The Focus of Research7

1.3 Logic and AI8

1.3.1 The Declarative vs.Procedural Debate8

1.3.2 Logics and Programming Systems9

1.3.3 Logic and Reasoning11

1.4 Points of Departure12

1.5 The Structure of this Book13

2 THE ROLE OF LOGIC IN LEGAL REASONING15

2.1 Three Misunderstandings about Logic16

2.1.1 ‘To Formalize is to Define Completely’16

2.1.2 ‘Formalization Leaves No Room for Interpretation’17

2.1.3 ‘Logic Excludes Nondeductive Modes of Reasoning’18

2.2 The ‘Deductivist Fallacy’18

2.2.1 ‘Naive Deductivism’19

2.2.2 The Criticism20

2.2.3 The Misunderstanding23

2.2.4 The Merits of the Criticism25

2.3 Noninferential Reasoning with Logical Tools26

2.4 Rule-based and Case-based Reasoning30

2.5 Summary31

3 THE NEED FOR NEW LOGICAL TOOLS33

3.1 The Separation of Rules and Exceptions in Legislation34

3.1.1 Terminology35

3.1.2 Examples36

3.1.3 Formalizations in Standard Logic37

3.1.4 Nonstandard Methods41

3.2 Defeasibility of Legal Rules47

3.3 Open Texture49

3.3.1 Classification Problems50

3.3.2 Defeasibility of Legal Concepts52

3.3.3 Vagueness54

3.4 Which Nonstandard Techniques are Needed?55

3.4.1 Reasoning with Inconsistent Information55

3.4.2 Nonmonotonic Reasoning56

3.5 AI-and-law Programs with Nonstandard Features61

3.5.1 The Law as Logic Programs61

3.5.2 TAXMAN ⅡⅡ61

3.5.3 Gardner’s Program62

3.5.4 CABARET63

4 LOGICS FOR NONMONOTONIC REASONING67

4.1 Nonmonotonic Logics68

4.1.1 Consistency-based Approaches68

4.1.2 Autoepistemic Logic73

4.1.3 Minimization76

4.1.4 Conditional Approaches87

4.1.5 Inconsistency Handling89

4.2 General Issues93

4.2.1 Preferential Entailment93

4.2.2 Properties of Consequence Notions94

4.2.3 Connections96

4.2.4 Truth Maintenance Systems97

4.3 Objections to Nonmonotonic Logics97

4.3.1 ‘Logic is Monotonic’97

4.3.2 Intractability99

5 REPRESENTING EXPLICIT EXCEPTIONS101

5.1 Introduction102

5.1.1 Methods of Representing Rules and Exceptions102

5.1.2 Kinds of Exceptions102

5.1.3 Requirements for Representing Rules and Exceptions103

5.2 Default Logic105

5.2.1 Specific Exception Clauses106

5.2.2 General Exception Clauses107

5.2.3 Evaluation111

5.3 Circumscription112

5.4 Poole’s Framework for Default Reasoning117

5.5 Logic-programming’s Negation as Failure120

5.5.1 Specific Exception Clauses121

5.5.2 General Exception Clauses122

5.5.3 Logic Programs with Classical Negation125

5.5.4 Summary129

5.6 Evaluation129

5.6.1 A Formalization Methodology130

5.6.2 Directionality of Defaults134

5.6.3 Contrapositive Inferences135

5.6.4 Assessment of the Exception Clause Approach136

6 PREFERRING THE MOST SPECIFIC ARGUMENT141

6.1 Introduction141

6.2 Poole: Preferring the Most Specific Explanation143

6.3 Problems148

6.3.1 Some Possible Facts are Irrelevant148

6.3.2 Multiple Conflicts Ignored149

6.3.3 Defaults Cannot be Represented in Standard Logic150

6.4 A System for Constructing and Comparing Arguments151

6.4.1 General Remarks151

6.4.2 The Underlying Logical Language152

6.4.3 Arguments154

6.4.4 Conflicts Between Arguments156

6.4.5 Comparing Arguments158

6.4.6 Informal Summary163

6.5 The Assessment of Arguments163

6.5.1 The General Idea163

6.5.2 The Dialogue Game Defined166

6.5.3 Illustrations170

6.6 Combining Priorities and Exception Clauses172

6.6.1 Extending the System172

6.6.2 Illustrations175

6.7 Evaluation177

7 REASONING WITH INCONSISTENT INFORMATION179

7.1 Introduction179

7.2 Existing Formalizations of Inconsistency Tolerant Reasoning180

7.2.1 AlchourronMakinson （1981）181

7.2.2 Belief Revision Approaches183

7.2.3 Brewka’s Preferred-subtheories Approach187

7.3 Diagnosis188

7.4 Hierarchical Defeat191

7.5 General Features of the System193

7.5.1 Properties of the Consequence Notion193

7.5.2 Sceptical and Credulous Reasoning195

7.5.3 Floating Conclusions196

7.5.4 Accrual of Arguments198

7.6 Conclusion200

8 REASONING ABOUT PRIORITY RELATIONS203

8.1 Introduction203

8.2 Legal Issues204

8.2.1 Legal Collision Rules204

8.2.2 Requirements for a Formal Analysis205

8.3 Extending the Definitions206

8.4 A Formalization Methodology210

8.5 Examples212

8.6 An Alternative Method217

9 SYSTEMS FOR DEFEASIBLE ARGUMENTATION219

9.1 Argumentation Systems219

9.2 Some Argumentation Systems221

9.2.1 The Bondarenko-Dung-Kowalski-Toni Approach221

9.2.2 Pollock226

9.2.3 Lin and Shoham229

9.2.4 Vreeswijk’s Abstract Argumentation Systems230

9.2.5 Nute’s Defeasible Logic232

9.2.6 Simari and Loui235

9.2.7 Geffner and Pearl’s Conditional Entailment235

9.2.8 General Comparison237

9.3 Other Relevant Research238

9.3.1 Brewka’s Later Work238

9.3.2 Reason-based Logic240

10 USING THE ARGUMENTATION SYSTEM249

10.1 A Comparison of the Methods for Representing Exceptions249

10.2 Implement at ional Concerns253

10.3 Applications255

10.3.1 Toulmin on the Structure of Arguments255

10.3.2 The System as a Tool in Reasoning256

10.4 A Logical Analysis of Some Implemented Systems258

10.4.1 Gardner’s Program258

10.4.2 CABARET261

10.4.3 Applications of Logic Metaprogramming262

10.4.4 Freeman and Farley’s DART System263

10.4.5 The Pleadings Game264

10.5 Four Layers in Legal Argumentation270

11 CONCLUSION275

11.1 Summary275

11.2 Main Results276

11.3 Implications for Other Issues281

11.4 Suggestions for Further Research284

A NOTATIONS, ORDERINGS AND GLOSSARY287

A1 General Symbols and Notations287

A2 Ordering Relations288

A3 Notions of the Argumentation System of Chapters 6-8289

A4 Glossary289

REFERENCES293

INDEX303