Expert’s (meta)testimony : an epistemological perspective

Expert witnesses play an important role in a legal process. Courts often appoint up to several experts to help resolve a specific factual case at hand. The mere fact that a judge decides to appoint experts to provide special information suggests that from the judicial perspective, such experts are (1) epistemically superior to a judge and (2) equals, i.e. epistemic peers with respect to each other. The problem arises when the opinions provided by two or more experts differ substantially. In our paper, we would like to address how such disagreements can be resolved by means of the institutional structure of the judicial process. For example, a judge may be allowed to evaluate the opinions herself to appoint another expert witness, or to ask for a meta-testimony (meta-opinion). The following issues arise: How can a judge, lacking of special knowledge, assess the correctness of expert opinions (as inferior on the epistemic level)? A judge has no grounds to provide a reliable argument as to which opinion is more plausible. An appointment of another expert may be an instance of “cherry-picking”. As we will argue, in cases where experts are not able to discuss their differences (conciliate) in order to reach a joint opinion, it might be best to appoint a meta-expert who will assess the reliability and correctness of disagreeing opinions. At the end of the paper, we provide certain normative, de lege ferenda suggestions as how to shape the institution of a meta-expert in legal proceedings.