One important technique used in the solution of sophisms was expositio, which typically turns a sentence containing a problematic term or expression into a conjunction of two or more simpler sentences. Thus, for example, “Socrates begins to be white’’ equals ‘‘Socrates is not white and immediately Socrates will be white.’’ Although expositio was a very general logical technique, the sophisms on beginning and ceasing - on limit-decision problems - can be singled out as an especially important group of such sophisms where also questions of natural philosophy were dealt with.
Epistemic logic was one central interest of Richard Kilvington and William Heytesbury in their respective collections of sophisms. Kilvington’s sophism 47, for example, is ‘‘the king is seated,’’ when it is assumed that if the king is seated, you know that he is, and if he is not seated, you know that he is not. The gist of the sophism is that you may be forced to doubt whether you know that the king is seated, and whether such doubt is in general possible. Also William Heyetesbury addresses the issue in his sophisms.
One interesting group of fourteenth-century sophisms concerns insolubles. For example, John Buridan’s Summulae de dialectica contains as the last part of the work a large collection of sophisms, including a group of 20 sophisms dealing with self-referential paradoxes. As Buridan does not tackle insolubles seriously anywhere else in his logic, it seems safe to suppose that at least he did not take sophisms simply as a teaching tool. Rather, sophisms were also considered a methodology for serious study.
See also: > Insolubles > John Buridan > Oxford Calculators > Richard Fishacre > Richard Kilvington > Richard Rufus of Cornwall > William Heytesbury
World History
