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Language, Proof and Logic


Language, Proof and Logic includes four pieces of software:

Grade reports are returned to the student and, if requested, to the student's instructor, eliminating the need for tedious checking of homework. All programs are available for the Windows, Macintosh and Linux platforms. Instructors do not need to use the programs themselves in order to be able to take advantage of their pedagogical value.

Current Versions

The current release for all supported operating systems is Frege (17.12, December 2017) which consists of: Boole 4.2.0, Fitch 3.7.0, Submit 3.1.0, and Tarski's World 7.2.4 and the second edition of the textbook and manual.

Supported Operating Systems: Mac OS X, 10.7 and above; Windows 7, Windows 8 and Windows 10; and 64 bit versions of the most recent long term support releases of Fedora and Ubuntu Linuxes.

The software can be downloaded by logging in using your registration id.



Boole is an aid for creating truth-tables. It includes an option to automatically generate the columns of the truth-table, although this option is disabled in the earliest exercises. Boole can be used to check the truth-table, either as it is being built or when it is complete, and to assess sentences of first order logic.


Fitch is a tool for building formal proofs in the format presented in LPL. The instant feedback that Fitch provides, in verifying each proof and marking steps that do not check out properly, makes it possible for students to correct and learn from their mistakes without the intervention of an instructor.

Tarski's World

Tarski's World is an environment in which students can evaluate sentences of first order logic. The students can create worlds, each of which consists of a chess-like board with blocks of various shapes and sizes positioned on it. Sentences are evaluated in the worlds, which can demonstrate counter-examples to the arguments presented in exercises. The program provides them with a Henkin-Hintikka game that leads them to understand where they went wrong. Using this program students quickly master the meaning of the connectives and quantifiers, and soon become fluent in the symbolic language at the core of modern logic.


Submit is a very different application. It is used to send exercise files created in the other three applications to the Grade Grinder. The student must enter a registration id, which is provided as part of the purchase, in order to use Submit. He or she must also enter their name and email address. The instructor's name and email address are optional. After the Grade Grinder verifies the student's Book Number, name, and email address, it receives the files. The files are graded and a grade report is sent out, by email, from the Grade Grinder to the student. If the student has chosen to submit to an instructor as well, the instructor's name and email address are verified and an email is sent to him or her.

...For more about Grade Grinder, click here .