Eleusis

About this board game

Eleusis is a 4–8-player card game that simulates the scientific method, with each game taking about 20 minutes. One player becomes “God,” “Nature,” or the “Demiurge” and secretly creates a law of nature governing which cards may be played correctly.

The other players are the Scientists. Taking turns, they perform experiments by playing cards and observing whether each play follows the hidden rule. They race to form a reliable hypothesis, with the first player to correctly deduce the rule scoring big. The rule may be straightforward, such as alternating black and red cards, or more difficult to discover, such as alternating cards whose numbers or letters contain closed loops with cards that do not.

• Secret rule deduction: infer the law from successful and unsuccessful card plays.
• Scientific experimentation: test ideas by playing cards and studying the results.
• Prophet challenge: a player with a hypothesis may predict the outcomes of other players’ experiments.
• Falsification: opponents can seek an experiment the Prophet cannot predict, potentially overthrowing the hypothesis and becoming Prophet themselves.

The hidden rule should be challenging but discoverable. If nobody works it out, God does not score; God’s score also depends on how long the Scientists take to find the answer. This creates a balance between choosing a clever rule and giving the experiment enough information to reward careful observation.

To play Eleusis, you need two packs of cards, a table, and paper and pencil. First published in Martin Gardner’s Scientific American column in June 1959, the game later received a revised version known as New Eleusis.