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Galen's Logic: Aristotelian Heritage or Scientific Innovation?
The subject of inquiry is Galen's logical heritage where some aspects are distinguished which are closely connected with his medical practice. In this respect most interesting proved to be his views on hypothetical logics, especially from the point of view of his slogan 'Pay attention to things not words'. Galen thinks that there are three ways in which a pair of states of affairs might be related: they might be in conflict, in consequence, or in neither relation. This Galen's classification of relations between states of affairs might be represented in form of a specific ontological square. Traces of Galen's conceptions are trailing in modern logic particularly in the systems of non-fregean and relevant logics having situational semantics. Thus, in the framework of non-fregean logic from "Q situationally involves P" follows "if P then Q" (but not vice versa) which meets Galen's slogan. Rather different, more complicated situational semantics of relevant logic also displays the signs of Galen's logical attitude. Such semantics allows to take into account the closeness of relevant implication to the natural language conditionals while in Galen's reasoning we most often deal namely with conditionals which best of all describe the situations occurred during the disease diagnostics by virtue of its hypothetical nature. To some extent semantics of such conditional descriptions would be employed in computer medical diagnostics. In this case the modern physician inevitably should be a logician like he was in Galen's time.