The assessment of argumentation based on abduction

Abduction is a widely used but deductively invalid type of reasoning. In this paper I will develop a tool for the assessment of argumentation based on abduction that can be used to analyse and evaluate the type of argumentation as it occurs in institutionalized contexts like science and medical diagnosis. I will summarize the most important definitions of abduction and propose an argumentative pattern on the basis of a critical examination of two extant dialectical accounts of the argument scheme involved