86. Rules of Division. -- Like definition, division plays a twofold part: one, fundamental, in the scientific order; the other secondary, in the paedagogic order.

I. From the first point of view the rules of division are: It must be complete; rationally progressive; if possible, positive.

II. In a second point of view, the division is made for the orderly arrangement and clarification of concepts. For this purpose it must he complete, clear, and methodical.^{1}

{1} The authors of Port Royal point out that it is "equally a defect to make too few and too many divisions; the one does not sufficiently enlighten the mind, the other dissipates it too much."