Blackwell Reference Online

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Influenced by the earlier work of, in particular, Alan Ross Anderson (1967), StigKanger (1957; Kanger and Kanger 1966), and Georg Henrik von Wright (1963), Ingmar Pörn produced in 1970 a work entitled The Logic of Power.The aim of the book was to develop some modal-logical tools and to apply them to the characterization of such concepts as influence, control, right, and norm– concepts which figure centrally in our understanding of social systems. Not surprisingly, a logic of action was one of the core components of Pörn's formal-logical framework.Action sentences of the kind(1) John opens the doorwere assigned the logical form(2) Di Ato be read as ‘i brings it about that A,’ where Di is a relativized modal operator and A describes the state of affairs brought about. Pörn (1970: 4–5) recognized that the logical form he adopted for (1) was a simplification. Although (1) entails(3) John brings it about that the door is open.(3) certainly does not entail (1). If, for example, it is the case that(4) John keeps the door openthen (3) is true whilst (1) may well be false. As Pörn pointed out, the difference in sense between (1) and (4) may be explained by reference to pairs of successive occasions. The truth of (1) requires that, on the earlier of two occasions, the door in question is not open, and then John does what he does and – as a result – the door is open on the later occasion. ... log in or subscribe to read full text