Paper short abstract:

The paper discusses how forensic scientists in the Swedish criminal justice system use a Bayesian approach to make uncertainty quantifyable, manageable, and communicable.

Paper long abstract:

Based on ethnographic fieldwork, I will discuss how forensic scientists in the Swedish criminal justice system use a particular quantitative approach to evaluating forensic laboratory results, the Bayesian approach, as a means of quantifying uncertainty and communicating it to judges, prosecutors, and defense lawyers. Their use of the Bayesian approach brings about a particular type of intersubjectivity; in order to make different types of forensic evidence commensurable and combinable, quantifications must be consistent across forensic specializations, which brings about a transparency based on shared understandings and practices. Finally, the Bayesian approach is also a means of distributing responsibility between the laboratory and the court.