The expressivist is poised to explain how supervaluationism developed into the most respected theory of vagueness. Frege portrayed vagueness as negligent under-definition: One haphazardly introduces a necessary condition here, a sufficient condition there, but fails to supply a condition that is both necessary and sufficient. Supervaluationists counter that indecision can be both intentional and functional. Instead of committing ourselves prematurely, we fill in meanings as we go along in light