Chapter 3: The Categories & the Predictables

Notes re: Scott Sullivan's An Introduction to Traditional Logic


Chapter 3


         Primary substance is an individual existent, e.g., Socrates

         Primary substance is not a category

         Primary substance does not exist in something

         Secondary substance is universal or nature, e.g., human being

         Secondary substance is a category

         Secondary substance is predicated of a primary substance


         Modify the way a primary substance exists

         Exist only in primary substances


         Ten categories = secondary substance + nine accidents

         Is a secondary substance an accident, i.e., does a secondary substance modify the way something exists?


o   No, because an individual existent (a primary substance) has the kind of existence which it has as a specific kind of existing being only through a secondary substance.

o   This is perhaps the sense in which we should take Sullivan’s assertion that the secondary substance is the main category (existing as a universal predicate)

 Predicables  Understanding Predicables

         If categories are the predicates of a subject, then the predicables are the ways in which the predicates are related to a subject

         Genus + specific difference = species

         Is every species a secondary substance?

         Is a genus ever a secondary substance?


o   Sullivan characterizes both species and secondary substance as the “nature” of a thing

o   Sullivan also characterizes “living” as a species (of corporeal things)

o   But “human being” and “living” are not species in the same sense or to the same degree

o   “living” doesn’t get as close as “human being” to revealing the reality of Socrates

o   Is Sullivan using species in an equivocal way?


§  To refer to the nature of an existent (i.e., a primary substance) AND

§  To refer to a subclass of a larger class?


         Characteristic that always accompanies a particular nature

         Distinguished from accident, which is a characteristic that can be said of things with different natures