Koan

There is a hidden rule that decides whether a word resonates or stays silent, and you are never allowed to ask what it is. Instead you probe: submit a word, learn how the oracle classifies it, and build a hypothesis from the pattern. Then you sit the certification — classifying fresh words yourself — and passing it is what counts as having found the rule.

• Probing is the only way to gather evidence, and every probe costs you score.
• You can never query the rule directly or have it confirmed in words.
• Certification presents words you have not seen and asks you to classify them.
• Passing proves the rule by using it rather than by stating it.
• The whole run is deterministic from its seed, so the same puzzle behaves identically each time.

• Daily, one shared hidden rule for everyone each day.
• Practice, endless fresh rules to test your deduction.
• Difficulty, choose Easy, Medium or Hard to set how subtle the law can be.

• Desktop: type a word and press Enter, or click the on-screen controls.
• Phone & tablet: use the on-screen keyboard and tap to submit, fully touch playable.

• Probe to distinguish, not to confirm. A word your current hypothesis already predicts teaches you nothing and still costs you.
• Change one thing at a time. Two words differing in a single feature isolate that feature; two unrelated words tell you almost nothing.
• Deliberately probe words you expect to be silent. A hypothesis is only worth holding once you have tried to break it.
• Certify as soon as your rule survives a genuine attempt to falsify it. Extra probes past that point are just spent score.
• If certification fails, the useful information is which word fooled you — the rule is usually narrower than the one you formed.

Probing a hidden rule by submitting examples and watching how they are classified is inductive-logic play, a tradition running from Robert Abbott's Eleusis — invented in 1956 and published by Martin Gardner in Scientific American in 1959 — to Kory Heath's Zendo, where the structures you build to test the rule are themselves called koans.

The original element is the certification: at some point you stop probing and stake the run on stating the rule.

Eleusis is often described as a model of the scientific method, and the certification is where this version presses on that. Gathering more evidence is always safe and never sufficient, so the game measures the thing induction actually costs — knowing when you have enough.

Koan is an original free browser game in the hidden-rule induction genre, where the whole challenge is inferring an unstated law purely from how it classifies the words you throw at it.

A free, original browser game on PlayPendium. No download, no install.