The Game of Logic

The Game of Logic is a book published in 1886 by the English mathematician Charles Lutwidge Dodgson, better known under his literary pseudonym Lewis Carroll. Besides his well-known children's literature, Dodgson was an academic mathematician who worked in mathematical logic. The book describes, in an informal and playful style, how a board game can be used to represent logical propositions and inferences.

The game is built around the proposition "Some fresh cakes are sweet." The board is divided into four quadrants, each representing a variation of that proposition: cakes that are fresh and sweet, fresh but not sweet, neither fresh nor sweet, and not fresh but sweet. Players use five grey coins and four red ones, where a red coin stands for the presence of cakes in an area and a grey coin for their absence. Each quadrant is further divided into edible and non-edible cakes, which allows players to handle more complex propositions and syllogisms. The second half introduces a 2x2x2 diagram for solving problems involving three propositions at once.

Dodgson later incorporated the game into a longer and more formal introductory textbook, Symbolic Logic, published in 1897. The two books are sometimes reprinted in a single volume.