Adaptive logics for non-explanatory and explanatory diagnostic reasoning

In this paper we discuss diagnosis of faults in systems. The latter are understood as structured wholes of components. Three types of diagnosis can be distinguished and are defined: non-explanatory, weak explanatory and strong explanatory. After the analysis of the reasoning process that leads to non-explanatory diagnosis, we argue that the predicative adaptive logic D-nexp is an adequate tool for modeling this kind of diagnostic reasoning. Subsequently, we follow the same pattern for weak and strong diagnosis and describe the logic D-exp which adequately formalizes weak diagnostic reasoning, even when underlying theoretical knowledge is taken into account. Finally it is argued that the same logic can be applied in the case of strong diagnostic reasoning whenever a number of conditions are fulfilled