There have been relatively few attempts to use fuzzy set theory or soft computing methods to dissect or portray inconclusive reasoning in law. From the perspective of a legal professional who is interested in rigorous study of uncertainty in law, this gap in research in fuzzy logic and soft computing is lamentable. Notions such as fuzzy and rough sets and logical procedures such as those described by fuzzy inference rules are extraordinarily evocative of notions and procedures that are routinely found in argument in legal contexts such as litigation. It seems obvious that a major research project on soft computing and uncertain legal argument should be launched. However, recent experience with attempts to use the standard probability calculus to dissect uncertain reasoning in law about factual questions suggests that before a major research project on soft computing and law is begun, interested soft computing researchers and interested legal professionals should try to reach agreement about the possible distinct purposes that any given mathematical or logical analysis of inconclusive legal argument might serve. Putting aside the special (and comparatively uninteresting) case of mathematical methods, or formal methods, that make their appearance in legal settings because they are part of admissible forensic scientific evidence, mathematical or logical analysis of inconclusive argument in law could have any one (or more) of the following distinct purposes (but research could and should explore the extent to the realization of any one of the purposes of formal analysis enumerated below might advance one or more of the other purposes enumerated below):
1. To predict how judges and jurors will resolve issues in litigation.The [non-existent] paper discusses the distinctive characteristics of these various purposes from a legal perspective.
2. To devise methods that can replace existing methods of argument and deliberation in legal settings.
3. To devise methods that mimic conventional methods of argument in legal settings.
4. To devise methods that support or facilitate existing, or ordinary, argument and deliberation in legal settings by mathematically illiterate actors such judges, lawyers, and jurors.
5. To devise methods that would capture some but not all ingredients of argument in legal settings about factual questions or legal questions.
6. To devise methods that perfect – that better express, that improve the transparency of – the logic or logics that are immanent, or present, in existing ordinary inconclusive reasoning about uncertain hypotheses that arise in legal settings.
7. To devise methods that have no practical purpose – and whose validity cannot be empirically tested – but that (ostensibly) serve to advance understanding of the nature of inconclusive argument about uncertain hypotheses in legal settings.
Coming soon: the law of evidence on Spindle Law