Many theorists have regarded genealogy as an important technique for social criticism. But it has been unclear how genealogy can go beyond the accomplishments of other, more mundane, critical methods. I propose a new approach to understanding the critical potential of history. I argue that theorists have been misled by the assumption that if a claim is deserving of criticism, it is because the claim is false. Turning to the criticism of concepts rather than criticism of claims, I expand on the distinction between “descriptive semantics” and “foundational semantics” to show that genealogy can be uniquely qualified to explore the foundations of concepts, and hence to criticize concepts that are problematic in nonobvious ways.