Relative plausibility versus probabilism: A level-of-analysis error in juridical proof

TL;DR

This paper clarifies that relative plausibility theory and probabilistic approaches in juridical proof operate at different conceptual levels, making them compatible rather than conflicting.

Contribution

It applies Marr's levels of analysis to show the compatibility of RPT and probabilistic approaches in legal reasoning, resolving longstanding disputes.

Findings

RPT provides a computational-level description of juridical proof.

Probabilistic approaches offer algorithmic-level accounts for calculations.

Relative plausibility aligns with posterior odds under coherence conditions.

Abstract

Debates about juridical proof are often framed as a conflict between probabilistic approaches and relative plausibility theory (RPT). This paper argues that this opposition rests on a level-of-analysis error. Drawing on Marr's distinction between levels of analysis, we show that RPT and probabilistic approaches operate at different conceptual levels and are therefore compatible rather than competing theories. RPT provides a computational-level description of juridical proof, characterizing the task of comparing explanations in light of the evidence and assessing whether a standard of proof has been met. Probabilistic approaches supply algorithmic-level accounts that specify how such comparative assessments can be represented and computed. When plausibility judgments satisfy minimal coherence conditions, relative plausibility corresponds to posterior odds. Recognizing this distinction clarifies longstanding disputes and highlights the complementary roles of explanation and probability in legal reasoning.