Tarski's World

The package is intended as a supplement to any standard logic text or for use by anyone who wants to learn the language of first order logic. The main body of the book contains a collection of exercises which use the Tarski's World software to teach the language and semantics of first order logic. The Tarski's World application allows the evaluation of first-order sentences within blocks world which users may construct using a simple editor. The worlds consist of collections of blocks of varying sizes and shapes, and placed on a checkerboard. We use an interpreted first-order language which allows users to write sentences about these worlds and evaluate their truth. A Henkin-Hintikka game may be used to elucidate the evaluation procedure.



Tarski's World (Tarski) is published by CSLI Publications and distributed by the University of Chicago Press. Tarski's World (Revised and Expanded Edition) supercedes previous editions of Tarski's World. The text is significantly revised, with the addition of many more exercise and an update to the old manual for the program. In addition, many of the exercises can be graded automatically using the Grade Grinder, the online grading service.

Online Course

We constructed an online course, the Semantics of First-Order Logic, based on the Tarski's World courseware package, with lectures by the authors. With more than six hours of video, the course covers the the syntax and semantics of both propositional and first-order logic. The course is divided into 4 parts each containing between two and four individual lectures. We recommend studying approximately one part per week. You can sign up at Edx to get access to video lectures, quizzes and assignments. Or watch the videos here on our website.


The package includes two pieces of software: Tarski's World, a program that teaches the basic first-order language and its semantics; Submit, a program that allows students to submit exercises done with the above programs to the Grade Grinder, the online grading service. Grade reports are returned to the student and, if requested, to the student's instructor.