Professor Susanne Bobzien

I have currently three main research interests, two in ancient logic, one in contemporary philosophy. First, I aim to improve our understanding of Stoic logic by bringing out similarities and dissimilarities to contemporary logic. Thus comparison of Stoic sequent logic with contemporary proof theory shows the Stoic system to be an unusual Gentzen-style relevance logic with backward proof search; comparison with contemporary first-order logic suggests Stoic logic contains the elements required for a theory of multiple generality with a variable-free syntax; comparison with Frege’s philosophical work indicates a wide-ranging dependency on the Stoics. The second, more historical, project traces hypothetical syllogistic from Aristotle to Boethius. My main contemporary interest is in vagueness and the Sorites paradox. I argue that the Kripke-complete normal first-order modal logic QS4M+BF+FIN holds the key to a generic solution for the Sorites. To this end, I have introduced the notions of columnar higher-order vagueness, semi-determinability and borderline nestings. An empirically based combination of contextualism and assessment sensitivity is central to the solution and the theory of vagueness that comes with it. Other interests include the semantic paradoxes and determinism, freedom, and moral responsibility.