tl;dr: Grant Sanderson (3Blue1Brown) argues that as AI increasingly generates proofs, mathematics should formally elevate "motivated explanations"—work that clarifies *why* theorems are true and how one might discover them—to the same academic status as proving open problems. He proposes concrete steps like defining "open exposition problems" analogous to Millennium Prize problems, creating dedicated journals, and weighting exposition in tenure decisions. He frames this cultural shift as both a response to AI and an opportunity to reassure young mathematicians that human understanding, not proof-generation, is the field's true goal.