Back to the future: Dimensions revisited

Citation: Trevor Bench-Capon and Edwina L. Rissland (2001) Back to the future: Dimensions revisited. JURIX 2001 (RSS)
Internet Archive Scholar (search for fulltext): Back to the future: Dimensions revisited
Tagged: Computer Science (RSS) argumentation (RSS), factors (RSS), dimensions (RSS), legal argumentation (RSS), case-based reasoning (RSS)

Summary

This paper distinguishes between factors and dimensions, and argues for revisiting and taking account of the more complex notion of dimensions. It sits in the larger context of legal and case-based argumentation and argumentation theory.

Two main differences are presented between factors and dimensions: Whereas factors are either present or absent, dimensions are on a continuum. Dimensions, per se, do not decide a case for one party or the other. The following definitions are presented:

Factor

• A feature that may be present or absent (all or nothing).
• A feature is applicable if it is present. In that case, the factor "always strengthens the case for the same disputant, either the plaintiff or the defendant"

Dimension

Dimensions represent ranges, not binaries. They "are designed to capture the knowledge that a legal problem can be approached in a certain way." They have three elements:

1. one or more prerequisites-some fact(s) that make the dimension applicable to this case.
2. one or more focal slots-fact(s) that determine the position in the range applicable to this case.
3. a direction-one extreme favours the plaintiff, and the other extreme, the defendant.

Advantages of Dimensions over Factors

• The same fact can be used by both parties.
• It adds more flexibility about whether two situations are treated similarly.
• "We can ascribe different degrees of strength to different positions within the dimension."

Other contents

Various older legal systems that used dimensions, e.g. HYPO (see Ashley 1990), CATO (see Aleven 1997), CABARET (see Rissland & Skalak 1991) , BankXX (see Rissland et al 1996).

The paper also discusses two case studies in detail.

Selected References

• Aleven, V. Teaching Case Based Argumentation Through an Example and Models. PhD Thesis. The Uni-versity of Pittsburgh,1997.
• Ashley. K. D. 1990. Modeling legal argument: Reasoning with cases and hypotheticals. Cambridge, MA: MIT Press
• Rissland, E.L., & Skalak, D.B. CABARET: Statutory interpretation in a hybrid architecture, International Journal of Man-Machine Studies (IJMMS), 34 , (1991) 839-887.
• Rissland, E.L., Skalak, D.B., & Friedman, M.T. BankXX: Supporting legal arguments through heuristic retrieval. Artificial Intelligence and Law . 4, (1996) 1-71.

Theoretical and Practical Relevance

This paper argues that case-based reasoning is now able to take account of more complexity, and that the simplification of factors should be reconsidered, to account for fuller decision criteria called dimensions.