more on this theme | more from this thinker | more from this text
Full Idea
In modern notation we can consider potential logical principles that Aristotle never considered because of his general practice of looking at inferences each of whose premises involved exactly two class-names.
Gist of Idea
Modern notation frees us from Aristotle's restriction of only using two class-names in premises
Source
Hilary Putnam (Philosophy of Logic [1971], Ch.3)
Book Ref
Putnam,Hilary: 'Philosophy of Logic' [Routledge 1972], p.26
A Reaction
Presumably you can build up complex inferences from a pair of terms, just as you do with pairs in set theory.