Tarski's World

Tarski’s World is an interactive educational program designed to teach the semantics of first-order logic through visualization and experimentation. Learners build small 3D “worlds” populated by geometric blocks that vary in shape, size, and position, then write logical sentences using predicates, relations, identity, and quantifiers to test whether those sentences are true in the current model. The software provides immediate feedback, helping students see how changes to a world affect truth conditions, and encouraging them to construct countermodels to refine their understanding.

Widely used in introductory logic courses and for self-study, Tarski’s World develops intuition about concepts such as satisfaction, quantifier scope, and logical consequence. Its hands-on approach makes abstract ideas concrete, allowing users to explore models, check sentences, and iterate quickly as they learn.

Tarski's World is developed by The Openproof Project, CSLI, Stanford University. The most popular version of this product among our users is unknown. The name of the program executable file is Tarski's World.exe.