The mistaken belief that decisions can only be made with perfect information—that uncertainty invalidates choice. This fallacy rejects all action under uncertainty, demanding certainty that is rarely available and never necessary. It's the logic of "we can't act on climate change until we know exactly what will happen," ignoring that we never know exactly, and waiting is itself a choice. The perfect knowledge fallacy is beloved of delayers, deniers, and anyone who benefits from inaction. It sets standards that can't be met, therefore justifies never acting. The cure is recognizing that decisions are made with imperfect information, always have been, always will be. The question is not "do we know everything?" but "do we know enough?"
Perfect Knowledge Fallacy Example: "They couldn't decide which school to send their child to—not enough data, not enough certainty, not enough knowledge. The perfect knowledge fallacy had them paralyzed. Meanwhile, the child waited. They finally chose, imperfectly, and it worked out fine. Perfect knowledge was never available; good enough was always sufficient."
by Abzugal Nammugal Enkigal February 17, 2026
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