Peirce's law of fallibilism holds that every belief we treat as settled is, technically, a hypothesis we've stopped testing. Charles Sanders Peirce, the nineteenth-century American logician, went further than most thinkers dare: he argued that the very act of adopting a belief as a working model changes your perceptual apparatus — you begin filtering incoming experience through it, which means the model protects itself from the data that would falsify it. This is the hidden cost of a well-organized mind. The mental models you rely on most fluently are precisely the ones most likely to be quietly shaping what you notice and what you screen out. Peirce's prescription, which he called 'the method of tenacity' versus 'the method of inquiry,' was to distinguish between beliefs you hold because they're comfortable versus beliefs you hold because you've genuinely kept the question open. The concrete move: pick one framework you reach for automatically — about productivity, about how your body responds to stress, about what kind of rest you need — and ask yourself when you last encountered something that didn't fit it. Not evidence against it. Just friction. That moment of friction is Peirce's signal that the inquiry should still be live.

What is the last piece of friction — a result, a feeling, a pattern — that your most-used framework quietly explained away instead of actually accounting for?

Drawing from Pragmatism / American Semiotics — Charles Sanders Peirce (The Fixation of Belief, 1877)