Simple logical structures of medical reasoning and action

The aim of this study is to delineate the fields of research on medical problem solving and action in which the use of logical methods may be fruitful and to describe the topics related to these fields in a way which would make easier further formal analysis. Four types of reasoning, namely, direct inference, verification of hypotheses, proving and explanation, are distinguished; simple examples of their application in the diagnostic and therapeutic inference-making are presented, and a complex, systemic character of reasoning in actual situations is described. The remarks concerning logical questions connected with the time factor, uncertainty and health values indicate the main sources of difficult problems which appear in a formal analysis. Medical action is represented as a sequence of consecutive, parallel and ramified diagnostic and therapeutic stages; the role of the plan of action and the importance of the cooperation between the doctor and the patient are stressed.