This article investigates how Plato thinks we secure necessary motivational conditions for inquiry. After presenting a typology of zetetic breakdowns in the dialogues, I identify norms of inquiry Plato believes all successful inquirers must satisfy. Satisfying these norms requires trust that philosophy will not harm but benefit inquirers overall. This trust cannot be secured by protreptic argument. Instead, it requires divine intervention—an extra-rational foundation for rational inquiry.