ABSTRACT
In this paper we introduce diagnostic reasoning through a case study which demonstrates the presence of a mixture of theoretical and extra-theoretical thinking activities. The concept of “theoretical” abduction is the most suitable one for modeling the process of discovery but also of selecting prestored hypotheses, like in the case of diagnostic reasoning. However, as an internal inferential process, theoretical abduction does not capture many reasoning situations in which action plays a fundamental role. To account for those cases of “thinking through doing” in which action takes an epistemic role we propose to adopt the concept of manipulative abduction. Diagnostic reasoning represents a suitable example of reasoning in which manipulative “selective” abduction plays a central role next to theoretical abduction. To illustrate the epistemic role of actions and the distribution of the cognitive and epistemic effort we can observe in some diagnostic tasks, the paper considers the case of medical semeiology and the use of external medical tools.
