Resumen de In defence of subjectivity: Extending the argument for a transparent trial. (A support on “bayesian modelling of criminal cases as a whole. A philosophical reflection on dutch case law”)

Silvia Bozza, Franco Taroni, Colin Aitken

• This comment addresses the “prior challenge” in forensic Bayesian modelling, recently highlighted by Anne Ruth Mackor (2026). We argue that the perceived lack of frequency data is not an insurmountable obstacle but a misconception rooted in an outdated view of probability. By adopting a radical subjectivist perspective based on de Finetti’s teachings, we reframe probability as a coherent representation of a decision-maker’s state of knowledge. We advocate for a strict functional separation: forensic experts provide the likelihood ratio based on technical findings, while the court assigns prior odds based on the specific case context. Through sensitivity analysis, we demonstrate that the subjectivity of priors can be viewed not as a source of arbitrariness but rather as a transparent and auditable mechanism that enhances judicial accountability. Ultimately, the Bayesian model is presented as a logical necessity for preventing miscarriages of justice.