explicit definition See BETH ‘s DEFINABILITY THEO -. REM , DEFINITIO. exponible. In medieval logic, exponible propositions were those that needed to be expounded, i.e., elaborated in order to make clear their true logical form. A modern example might be: ‘Giorgione was so called because of his size’, which has a misleading form, suggesting a simple predication, whereas it really means, ‘Giorgione was called ‘Giorgione’ because of his size’. Medieval examples were: ‘Every man except Socrates is running’, expounded as ‘Socrates is not running and every man other than Socrates is running’; and ‘Only Socrates says something true’, uttered by, say, Plato, which Albert of Saxony claims should be expounded not only as ‘Socrates says something true and no one other than Socrates says something true’, but needs a third clause, ‘Plato says something false’.
This last example brings out an important aspect of exponible propositions, namely, their use in sophisms. Sophismatic treatises were a common medieval genre in which metaphysical and logical issues were approached dialectically by their application in solving puzzle cases. Another important ingredient of exponible propositions was their containing a particular term, sometimes called the exponible term; attention on such terms was focused in the study of syncategorematic expressions, especially in the thirteenth century. However, note that such exponible terms could only be expounded in context, not by an explicit definition. Syncategorematic terms that produced exponible propositions were terms such as ‘twice’, ‘except’, ‘begins’ and ‘ceases’, and ‘insofar as’ (e.g. ‘Socrates insofar as he is rational is risible’). See also SYNCATEGOREMATA. S.L.R.