Taming complexity: Rationality, the law of evidence and the nature of the legal system

Ronald J Allen*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    9 Scopus citations


    This essay explores the implications of complexity for understanding both the law of evidence and the nature of the legal system. Among the propositions critically analysed is that one significant way to understand the general problem of the meaning of rationality is as a multivariate search for tools to understand and regulate a hostile environment. The law of evidence is conceptualized as a subset of this effort, at least in part, as involving a search for tools to regulate the almost infinitely complex domain of potentially relevant evidence and at the same time to accommodate policy demands. The proposition is then considered that the legal system of which the evidentiary system is a part has emergent properties that may not be deducible fromits component parts, which suggests in turn that it may be, or at least has properties highly analogous to, a complex adaptive system. One implication of this analysis is that the tools of standard academic research that rely heavily on the isolation and reduction of analytical problems to manageable units to permit themto be subjected to standard deductivemethodologiesmay need to be supplemented with analytical tools that facilitate the regulation of complex natural phenomena such as fluid dynamics. This has direct implications for such things as the conception of lawas rules, and thus for the Hart-Dworkin debate that has dominated jurisprudence for 50 years. That debate may have mischaracterized the object of its inquiry, and thus the Dworkinian solution to the difficulties of positivism is inapplicable. It can certainly be shown that the Dworkinian solution is not achievable and cannot rationally be approximated. Solutions to legal problems within the legal system as a whole (as compared to any particular node within the legal system) are arrived at through a process of inference to the best explanation that occurs within a highly interconnected set of nodes similar to a neural or social network.

    Original languageEnglish (US)
    Pages (from-to)99-113
    Number of pages15
    JournalLaw, Probability and Risk
    Issue number2
    StatePublished - Jun 1 2013


    • Bayes Theorem
    • Complex adaptive system
    • Complexity
    • Computational complexity
    • Dworkin
    • Evidence
    • Hart
    • Inference to the best explanation
    • Legal theory
    • Probability
    • Rationality
    • Theory of law

    ASJC Scopus subject areas

    • Philosophy
    • Statistics, Probability and Uncertainty
    • Law


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