الْكُلُّ أَعْظَمُ مِنَ الْجُزْءِ
A whole is greater than its part.
This example assumes a part genuinely contained within the whole and a relevant comparison of quantity or extent. Once those concepts are properly specified, the relation need not be established through repeated experiments.
With first principles, a crucial task is conceiving the subject and predicate accurately. If someone uses “part” or “whole” in different respects, apparent disagreement may arise without defeating a properly specified principle.
One must therefore distinguish an evident judgment from a confused expression of that judgment. A failure to understand terms is not itself a counterexample to the correctly understood principle.