Abstract
Now we should have to answer the question: when were the questions on Perihermeneias written? Little is known about the chronology of Buridan's works. Even a relative date is difficult to establish. However, some remarks can be made. First, there is the fact that the questions on Perihermeneias are quoted several times in Tractatus I of the Summule (4), in a way that makes it highly probable that the Summule were written after the Questiones on Perihermeneias (5). Now, according to professor Pinborg the first lectura of the Summule may be dated as early as the late 1320es (6), that is at the very beginning of Buridan's career as a teacher of philosophy at the university of Paris. This may be an indication for an early date of the Questiones on Perihermeneias, possibly as early as 1325. There are two other reasons for assuming that the commentary on Perihermeneias is one of Buridan's first works. The first clue is given by the places where Buridan refers to one of his own works: once he refers to his commentary on Porphyry's Isagoge (7), twice to his commentary on Aristotle's Metaphysics (8), and six times to his commentary on the Physics (9). The way in which he refers to these tracts seems also to be significant: the reference to his commentary on Porphyry's Isagoge shows that this work is of an earlier date than the present work. As to the other two works, he only refers to the number of the book in which he is going to treat a particular subject, not to the number of the question. A (cross)reference to the Summule is not given, although, as Pinborg remarks, there is a general doctrinal concordance between the two works. The questions on Metaphysics do not contain a (cross)-reference to the questions on Perihermeneias, at least not on the places where one would expect them. I am not certain about possible references occurring in the commentary on Physics. However, we should be very careful to draw conclusions from the occurrence of references, since it is always possible that we are dealing with a second or third lectura of the text..