M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 2005 Towards Modeling Systematic Interpretation of Codified Law Matthias Grabmair University of Augsburg School of Law Germany Kevin D. Ashley University of Pittsburgh School of Law Intelligent Systems Program USA

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 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 code’s 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.

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 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.

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 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?

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference The Approach in a Nutshell Code INR IF-THEN relations with Interaction Predicates in isomorphic original code structure Generation Domain Knowledge Ontologies Rulebase Plain final rules

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 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.

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 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.

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 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

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference Core Concepts Ruleset Tree Sphere of Influence The set of norms a certain norm influences and by which it is influenced. Each node is a complete ruleset from the same static INR and inherits its mother node interpretations. §1 §§1,2 §§1,2,3

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference 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 AI&Law  Sharpen contours of legal methodology through experiment results  Correctly visualize a norm’s 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

M. Grabmair & K. D. Ashley Towards Systematic Interpretation of Codified Law Jurix Conference Thank You! Slides available at: