Full Idea
Universals are more explanatory (for something which holds in itself is itself explanatory of itself; and universals are primitive; hence universals are explanatory) - so universal demonstrations are better.
Gist of Idea
Universals give better explanations, because they are self-explanatory and primitive
Source
Aristotle (Posterior Analytics [c.327 BCE], 85b25)
Book Reference
Aristotle: 'Posterior Analytics (2nd ed)', ed/tr. Barnes,Jonathan [OUP 1993], p.37