Published online by Cambridge University Press: 17 October 2016
In the 1930s, C. I. Lewis, who was responsible for the revival of modal logic in the era of modern symbolic logic, characterized ‘intensional’ approaches to logic as typical of post-Leibnizian ‘continental philosophy’, in contrast to the ‘extensionalist’ approaches dominant in the British tradition. Indeed Lewis’s own work in this area had been inspired by the logic of his teacher, the American ‘Absolute Idealist’, Josiah Royce. Hegel’s ‘Subjective Logic’ in Book III of his Science of Logic, can, I suggest, be considered as an intensional modal logic, and this paper explores parallels between it and a later variety of modal logic—tense logic, as developed by Arthur Prior in the 1950s and 60s. Like Lewis, Prior too had been influenced in this area by a teacher with strong Hegelian leanings—John N. Findlay. Treated as an intensional (with an ‘s’) logic, Hegel’s subjective logic can be used as a framework for addressing issues of intentionality (with a ‘t’)—the mind’s capacity to be intentionally directed to objects. In this way, I suggest that the structures of his subjective logic can clarify what is at issue in the ‘Psychology’ section of the Encyclopaedia Philosophy of Subjective Spirit.