Rebooting the new evidence scholarship

Abstract

The new evidence scholarship addresses three distinct approaches: legal probabilism, Bayesian decision theory and relative plausibility theory. Each has major insights to offer, but none seems satisfactory as it stands. This paper proposes that relative plausibility theory be modified in two substantial ways. The first is by defining its key concept of plausibility, hitherto treated as primitive, by generalising the standard axioms of probability. The second is by complementing the descriptive component of the theory with a normative decision theory adapted to legal process. Because this version of decision theory is based on plausibilities rather than probabilities, it generates plausibilistic expectations as outputs. Because these outputs are comparable, they function as relative plausibilities. Hence the resulting framework is an extension of relative plausibility theory, but it retains deep ties to legal probabilism, through the proposed definition of plausibility, and to Bayesian decision theory, through the normative use of decision theory.

Here is a table: A prolegomenon to a future new evidence scholarship in Africa

“…This particular table has been fundamentally reconfigured in the Euro-American world by the now extant new evidence scholarship movement (Lempert, 1986; Lempert, 2001: 1622 and 1622, n13; Park, 1991: 854; Twining, 1999: 352, n4). While several scholars in that part of the world have said that ‘new evidence scholarship is no longer new’ (Pardo, 2013: 549; Welch, 2020: 351), this revolution is yet to arrive on African shores.…”

“…This latter example is mentioned here despite the fact that legal and evidential argumentation is currently dwarfed by the domineering Bayesian (or probabilistic) and ‘Bayesioskeptic’ debates (see Bex, 2011; Brewer, 1996: 923; Dahlman, 2017: 83; Feteris, 2017; Keptein, 2017; Kloosterhuis, 2005: 471; Perelman, 1963; Perelman and Olbrecht-Tyteca, 1969; Rieke, 1981: 152; Tuzet, 2013: 207; Verheij, 1999: 109; Walton, 2002, 2014). Welch pertinently points out that these debates are dominated by ‘two disparate groups,’ that is, ‘a pro group, disposed to build mathematical models’ and a ‘con group, critical of the juridical use of these models’ (Welch, 2020: 351). A few signs of convergence between these two groups have also recently began to emerge (Allen and Pardo, 2019: 206–207; Friedman, 2001: 2040–8; Gelbach, 2019: 169; Welch, 2020: 353 and 358–363).…”

“…Welch pertinently points out that these debates are dominated by ‘two disparate groups,’ that is, ‘a pro group, disposed to build mathematical models’ and a ‘con group, critical of the juridical use of these models’ (Welch, 2020: 351). A few signs of convergence between these two groups have also recently began to emerge (Allen and Pardo, 2019: 206–207; Friedman, 2001: 2040–8; Gelbach, 2019: 169; Welch, 2020: 353 and 358–363). On Schum's distinction between ‘structural’ and ‘force-related’ theorising (Schum, 1994: 62–3), much of Euro-American new evidence scholarship can be said to be predominantly preoccupied with the latter force-related variant.…”

(Im)probable stories

“…As I explained in chapter II, more and more evidence scholars suggest that these two accounts are compatible and may also complement one another. However, discussions about the relationship between the two mainly focus on how explanation-based thinking can lead to a justified high credence in first-order propositions (e.g., Hedden & Colyvan, 2019;Biedermann & Vuille, 2019, 18-20;Gelbach, 2019, 169;Welch, 2020). What I want to suggest here is that explanation-based thinking can (also) complement the Bayesian account on the level of the fact-finder's higher-order belief.…”

“…The idea that probabilistic tools may be used for analyzing and presenting evidence was popularized during a wave of legal proof that began in the 1980's and which has become known as the 'New Evidence Scholarship' (Lempert, 1986, 440;Welch, 2020). This generation of evidence scholars focused mainly on the scope, limitations, and appropriateness of explicitly using mathematical reasoning about probabilities at trial (cf.…”