This week’s virtual medieval colloquium will be a roundtable discussion on the history of logic.
When: Thursday, June 18, 2020, 5pm in the UK; 11am in Illinois.
Abstract: The modern word ‘paradox’ covers many types of medieval logical puzzles, including two types that the medieval Latin logicians called “sophismata” and “insolubilia.” Insolubilia are the logical paradoxes — semantic, such as the Liar (‘I am lying’ or ‘Every proposition is false’) and epistemic, such as the Knower (‘You do not know this proposition’) — while sophismata are ambiguous sentences where two seemingly equally good analyses can be provided leading to opposite conclusions about the truth of the original sentence. We will rehearse the re-discovery of Aristotle’s Sophistical Refutations in the Latin West in the 12th century and consider how sophisms and insolubles were deployed in logical analysis. Solutions by restrictio and cassatio, popular up to the time of Burley and Ockham, were replaced by the radically new solution due to Bradwardine and the subsequent variants it inspired in the 14th century, and others opposed to its basic idea. Finally, we will look at the independent development of solutions to the Liar in the Arabic tradition, starting with fragmentary evidence of discussion of the paradox in the 5th/10th century, then looking at several solutions proposed in the 7th/13th century by figures broadly associated with Naṣīr al-Dīn al-Ṭūsī’s “Marāgha School”, and finally turning to the extended debate on the Liar at the end of the 9th/15th century, between Jalāl al-Dīn al-Dawānī and Ṣadr al-Dīn al-Dashtakī.
Sponsored by the Paris Institute of Advanced Studies.