Full Idea
Plato's unity of science principle states that all - legitimate - sciences are ultimately about the Forms. Aristotle's principle states that all sciences must be, ultimately, about substances, or aspects of substances.
Gist of Idea
Plato says sciences are unified around Forms; Aristotle says they're unified around substance
Source
report of Aristotle (works [c.330 BCE], 1) by Julius Moravcsik - Aristotle on Adequate Explanations 1
Book Reference
-: 'Synthese' [-], p.4