De Finetti's subjectivism, the assessment of probabilities and the evaluation of evidence: a commentary for forensic scientists

This paper presents the historical and philosophical definition of subjecti ve probabilities (also called degree of belief or Bayesian probabilities). It presents a case for the scientist to use subjective probabilities in the process of parameter estimation and evidence evaluation under the Bayesian framework. It is emphasised that Bayesian methodology does not pretend to get the 'true' probabilities: it is an effective method to analyse, critici se, check the 'coherence' of people's opinions, and to help them in revisin g their opinions in a 'coherent' way.