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Browser-based Sentential Logic Calculator
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Browser-based Sentential Logic Calculator

"What is the case - a fact - is the existence of states of affairs."

-- Ludwig Wittgenstein, Tractatus Logico-Philosophicus p.2

Use TruthMachine on-line.

TruthMachine is a pure JavaScript browser based calculator for Sentential Logic (AKA Propositional Logic or Propositional Calculus). I've created it for fun and because I wanted to play around with writing parsers instead of doing my Introduction to Formal Logic course homework.

Initially the goal is to allow users to easily type in a Well-Formed Formula (WFF), parse it & validate it syntactically and generate a truth-table for it. Additional related features may be added in the future. There is great emphasis on ease of use.

It is intended to be educational and will hopefully help other students and teachers.

Supported Operators

Currently the following logical operators are supported, with their respective symbols (yes, you may be used to different ones):

  • ~ Negation
  • • Conjunction
  • ∨ Disjunction
  • ≡ Equivalence
  • ⊃ Implication

The lexer/parser is based on Jison so it should be relatively easy to add support for additional logical operators, as long as they are describable as a finite series of boolean arithmetic operations :P


Want to help out? See the list of tasks and bugs. If you're a programmer, fork the project and fix some of them. If you're one of those people who like to tell other people what to do or give them helpful advice (that's not necessarily a bad thing), you can create some feature requests as well.


TruthMachine is distributed under the terms of the New BSD License. That means it's free software - you are welcome to use it for any purpose with (almost) no strings attached. You are more than encouraged to contribute. See for licensing details.

(c) 2013 Shahar Evron, all rights reserved

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