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▶ CLASSICAL LOGIC·5–10 MIN

MODUS TOLLENS PRACTICE

The classical denying-the-consequent move. The fastest way to spot a broken conditional.

What this is

Modus tollens: if P then Q. Not-Q. Therefore not-P. The move is the engine of most theory-falsification.

The practice is small and useful: take a claim of the form 'if [theory], then [prediction].' Look at what's actually happening. If the prediction isn't happening, the theory takes a real hit — and you've just used modus tollens.

Steps

  1. 1.Pick a theoretical claim with a testable prediction. E.g.: 'If raising minimum wage to $15 causes unemployment, we'd see job losses in Seattle after the 2017 raise.'
  2. 2.State the conditional clearly: 'If P (theory), then Q (prediction).'
  3. 3.Check Q. What did actually happen?
  4. 4.If Q didn't happen: the theory is in trouble. (Not necessarily refuted — maybe the conditional was wrong, or other factors interfered — but it owes you an explanation.)
  5. 5.Try this with three of your own beliefs. What did you predict? What actually happened?
▸ AFTER

Which of your beliefs have you stopped checking against their predictions?

Reflections you write below are saved to your trajectory — Claude reads the prose and adds a small dimensional shift to your map, the same way it does for daily dilemmas and diary entries.

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▶ What to do next

Three doors lead onward.

  1. 01 · QUIZ
    The Inheritor
    Find your archetype — exercises hit differently when tuned to who you are.
    CONTINUE ▶
  2. 02 · NEXT EXERCISE
    Fallacy hunt
    Pick a real argument from the wild and find three reasoning errors in it.
    CONTINUE ▶
  3. 03 · DAILY
    The Crucible
    A philosophical action to actually do today. Tomorrow you report back.
    CONTINUE ▶