dont-fool-yourself

name

dont-fool-yourself

description

Run a belief, result, decision, or plan through a self-skeptic pass: what would I observe if this were wrong, what is the cheapest experiment that could falsify it, and what am I not counting because it's inconvenient. Turns a comfortable conclusion into a testable one. Use when the user says "sanity check this", "am I fooling myself", "what would prove me wrong", "stress-test my reasoning", "pre-mortem this", "내가 착각하는 거 아냐", "이 결론 검증해줘", "반증해봐", "이거 진짜 맞아". Do NOT use to quiz another person (use grill-me). Do NOT use to spot copied ritual in a design (use cargo-cult-detector).

Don't Fool Yourself

"The first principle is that you must not fool yourself — and you are the easiest person to fool. So you have to be very careful about that."

A conclusion feels most solid right when you most want it to be true. This skill is the discipline Feynman demanded of himself: bend over backwards to show how you might be wrong before you commit. It converts "I believe X" into "here is what would break X, and here is the cheapest way to check."

The five questions

Run the claim through all five. Answer them, don't just ask them.

1. Falsifier. If this were false, what would I see? Name a concrete observation. A belief with no possible disconfirming observation isn't knowledge yet.
2. Cheapest test. What is the smallest, fastest experiment that could produce that observation? (One query, one probe, one day of data — not a quarter-long study.)
3. Inconvenient evidence. What am I discounting because it complicates the story? Survivorship, the sample I didn't take, the failure I filed as a fluke.
4. Motivated reasoning. What do I want to be true here, and how would that wish shape which evidence I weigh? Name the wish out loud.
5. Strongest opposite. State the best case for the opposite conclusion — the version a smart adversary would make, not a strawman. If it's comparably strong, the honest verdict is "undecided", not your original claim.

Workflow

1. Restate the claim/result/decision in one falsifiable sentence.
2. Answer the five questions.
3. If a cheap test exists and hasn't been run — run it (or say plainly it must be run before acting). An untested falsifier is a to-do, not a pass.
4. Reissue the verdict with calibrated confidence: holds / holds-if <test passes> / undecided / overturned.

Output

• One-line falsifiable claim
• Answers to the five questions
• The cheapest test + its result (or "must run before acting")
• Calibrated verdict

Don't fool yourself (about this skill)

• Producing five tidy answers can itself be theater. The pass only counts if at least one answer changed your confidence or spawned a real test.
• "I couldn't think of a falsifier" usually means the claim is vague, not bulletproof. Sharpen it until it can be wrong.