The categories in Petrus Hispanus’s Tractatus commentators: John Buridan, John Versor and Peter Tartaret

One of the features of the manuscript transmission of Petrus Hispanus’s Tractatus (or Summulae logicales) is the fact that the treatise on the Categories does not always appear in the same place. In some manuscripts, it appears in third place, after the treatise on Porphyry’s Isagoge, following the traditional order of the logica vetus. But in some others, the treatise on the Categories appears in fifth place, after the treatise on the Topics and right before the treatise on supposition. In both cases, it seems that the place of Aristotle’s Categories in logic is defined by the notion of “term”. The purpose of this article is to understand why this variation occurs, since it is not theoretically neutral. Hence, to address the problem of placing the treatise on the Categories within logic, three of the most prominent Tractatus commentators will be presented: John Buridan, John Versor and Peter Tartaret. This exercise will provide some insights on the relation between the categories and the theory of supposition, and also on the vexata quaestio of what categories are about (words, concepts, or things).