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Puzzles, Charts & Dilemmas

Puzzles

Philosophy & Logic Puzzles

Named logic puzzles, not riddles, with every rule written down and each answer checked by exhaustive search, plus disputed paradoxes set out side by side.

Illustration: a man stands on a riverbank beside a small empty rowing boat, with a wolf, a goat and a cabbage waiting near him; the far bank is empty.

River Crossing Puzzle: Under Its Rules, Two Shortest Routes

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Illustration: Puzzles, Charts & Dilemmas. Generated schematic illustration — not a photograph or historical record. Reuse: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), to the extent Puzzles, Charts & Dilemmas holds rights in it.

Illustration: two men in matching grey suits stand on a small island, seen from behind; one raises an open hand as if speaking while the other stands silent with his arms at his sides.

Knights and Knaves: 108 of 256 Puzzles Have a Single Answer

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Illustration: Puzzles, Charts & Dilemmas. Generated schematic illustration — not a photograph or historical record. Reuse: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), to the extent Puzzles, Charts & Dilemmas holds rights in it.

Illustration: a man at a low table holds his hand above a closed box, next to an open tray stacked with blank slips; he has not touched either.

Newcomb's Problem: Rules Split if the Predictor Tops 50.05%

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Illustration: Puzzles, Charts & Dilemmas. Generated schematic illustration — not a photograph or historical record. Reuse: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), to the extent Puzzles, Charts & Dilemmas holds rights in it.

Illustration: a wooden Tower of Hanoi on a small board, eight discs stacked on the first of three pegs with the largest at the bottom; the two other pegs stand empty.

Tower of Hanoi: 8 Disks Need 255 Moves on Three Pegs

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Illustration: Puzzles, Charts & Dilemmas. Generated schematic illustration — not a photograph or historical record. Reuse: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), to the extent Puzzles, Charts & Dilemmas holds rights in it.

Illustration: a man stands before three identical closed doors set in a plain wall, seen from behind, one hand raised toward the middle door without touching it.

Unexpected Hanging Paradox: The Proof Fails, but Where?

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Illustration: Puzzles, Charts & Dilemmas. Generated schematic illustration — not a photograph or historical record. Reuse: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), to the extent Puzzles, Charts & Dilemmas holds rights in it.