  By Leśniewski’s own later and very exacting standards, this first formulation of Mereology is methodologically imperfect, because it intersperses axioms and definitions. A cleaner formulation would express all axioms in terms of the mereological primitive (here ‘part’) only. This would be possible in this case simply by substituting the definitions of defined terms in Axioms III and IV, but it would not be especially enlightening. It also results in an axiom system that can be substantially simplified, both by reducing the number of axioms and by simplifying and shortening them. These desiderata (fewer, shorter, and more perspicuous axioms) often pull in different directions.