Towards Modeling Systematic Interpretation of Codified Law

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Towards Modeling Systematic Interpretation of
Codified Law

• Matthias GrabmairUniversity of Augsburg School
  of LawGermany
• Kevin D. AshleyUniversity of Pittsburgh School
  of LawIntelligent Systems ProgramUSA
• http//www.plainreasoning.com

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Systematic Interpretation

• ... is one of the four recognized civil law
  interpretation methods besides wording,
  legislative intent and teleology.
• ... analyzes a norm with respect to its position
  in the codes overall structure and
  interconnected meaning.Larenz, 1995 Alexy
  1978
• ... means interpretation of norm interaction.
• The norm is interpreted in light of the influence
  of other norms ...
• ... and in light of the influence the norm has on
  its surrounding ones ...
• ... in its Sphere of Influence.

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Legal Sentences

• Complete Legal Sentences Larenz, 1995
• ... form a regulation by themselves because they
  mention all their requirements and consequences.
• ... can directly be translated into an IF-THEN
  relation.
• Incomplete Legal Sentences
• ... need to be read in conjunction with other
  legal sentences in order to construe an
  autonomous regulation.
• ... need systematic interpretation in order to be
  translated into an IF-THEN relation.

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Point of Departure

• How can a piece of written law be translated into
  a ruleset and, at the same time, capture the
  systematic interplay of its legal sentences
  authentically?

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The Approach in a Nutshell
INR IF-THEN relations with Interaction Predicates
in isomorphic original code structure
Rulebase Plain final rules
Generation
Code
Domain Knowledge Ontologies
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INR

• The Intermediate Norm Representation (INR)
  mirrors the code in its original structure in an
  isomorphic way using IF-THEN relations. Prakken
  Schrickx, 1994
• No exterior information is used in formulating a
  relation from the original legal sentence.
• Hooks for norm interaction and the sphere of
  influence are neutrally preserved through the use
  of Interaction Predicates.

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Interaction Predicates

• ... are used in the INR in the same way as
  standard binary predicates.
• ... symbolize standardized phenomena of norm
  interaction (e.g. referrals, exceptions, etc.)
• ... are equipped with encapsulated reasoning
  algorithms that are defined at the outset as the
  typical reasoning steps a jurist undertakes when
  encountering the respective norm interaction.
• The algorithms use code structure and domain
  knowledge ontologies to generate final,
  unambiguous rulesets and arrange them in a tree.
  Gardner, 1987
• Conflicts can be detected van Engers et. al.,
  2000 and solved through authentic legal
  reasoning.

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Example

• 1 For c, r1, r2 and r3 need to be fulfilled.
• INR IF (r1 AND r2 AND r3) THEN c
• Ruleset IF (r1 AND r2 AND r3) THEN c
• 2 In case of r4, r3 shall suffice.
• INR IF (r4) THEN suffice(r3)
• Reasoning of the suffice-Interaction Predicate
• 1 is determined as referenced norm out of the
  structure.
• Domain knowledge is used to determine implicit
  assumptions.
• Most plausible interpretation(s) spread out a
  ruleset tree.
• Ruleset (e.g.) IF (r1 AND r3 AND r4) THEN c

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Core Concepts
Each node is a complete ruleset from the same
static INR and inherits its mother node
interpretations.
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Ruleset Tree
1,2
1,2,3
The set of norms a certain norm influences and by
which it is influenced.
Sphere of Influence
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Further Challenges

• Issues
• Strong dependency on the definitions of
  ontologies and predicates
• Risk of oversensitivity, but necessary to capture
  subtleties
• Project Aims
• Contribute to norm interpretation research in
  AILaw
• Sharpen contours of legal methodology through
  experiment results
• Correctly visualize a norms sphere of influence
  in the code
• State of the Project
• In the phase of conceptualization
• Search for a suitable legal test field for a
  future experiment

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Thank You!

• Slides available at
• http//www.plainreasoning.com