Symbols: Learn Logic1.1.0 - App Store

Learn logic with Symbols, the app that teaches natural deduction and the rules of inference in an intuitive, accessible way. Our unique Studycards feature visual pictographs and interactive, step-by-step exercises that allow you to grasp each rule easily and quickly. Then, challenge yourself with activities specifically designed to practice those rules, building your skills progressively, and cementing them in your memory with every level completed.

Why Symbols?

Comprehensive Studycards: Learn essential rules like Modus Ponens, Modus Tollens, Disjunctive Syllogism, and many more through clear explanations and examples. Perfect for students and anyone looking to understand formal logic.

Engaging Activities for Skill Mastery:

Validity: Sharpen your critical thinking by evaluating pre-solved arguments. This unique activity provides the benefits of repetition without the tedium, helping you apply, recognize, and grow familiar with the rules of inference.

Justification: Challenge your understanding with puzzle-like scenarios where you deduce missing argument steps. This deepens your comprehension and refines your application of logical rules within complex arguments.

Inference: By this stage, the training wheels are off, and the student has to draw on everything they've learned so far. Their task is to mentally build a valid argument from what’s provided-or to recognize that no valid argument can be formed. What would normally be worked out slowly on paper is now done at the speed of thought.

Translation: Translation helps students practice turning statements with indicator words and phrases into logical form. These indicator words, commonly found in logic books and courses, give students a sense of how to translate everyday language into formal logic. Translation breaks this process into levels, allowing students to track their progress and earn new scores as they build proficiency.

Download Symbols for free and begin your journey into formal logic. Your free access includes the first level of every activity and the Modus Ponens study card, a must-have for getting started. For more advanced content and features, simply use our in-app purchases to continue building your logic skills.

Start your journey of mastering the rules of inference now!

Version History Symbols: Learn Logic now lets you easily review any questions you missed. A new "Review Incorrect Questions" section—added by popular request—appears at the end of each activity, so every step forward can be a little clearer.

Your feedback continues to shape the app. Thank you. 1.1.0 09/23/2025 Symbols: Learn Logic now has a streamlined onboarding flow, reduced app clutter, and general bug fixes for a better experience. 1.0.11 07/13/2025 The "Suggested Studycards" section in the Activity Detail page has been improved, and I added new animations to better communicate intent. Under the hood, build tools and underlying frameworks have been updated. Additionally, new users will benefit from a redesigned onboarding process that clearly explains what they get and the purpose of Symbols Logic. 1.0.8 03/26/2025 Minor bug fixes for later levels in "Justification" activity. 1.0.7 12/17/2023 General bug fixes, avoid unnecessary re-renderings, and solved some subtle UI issues. 1.0.6 04/22/2023 Resolved some UI issues and added another option for authentication. 1.0.5 04/18/2023 - Fixed an issue where tabs in Studycard Explanations were overflowing.
- Fixed an issue where Studycard Explanations were not restarting from the beginning when a new tab was selected.
- Fixed descriptions in Studycard Explanations. 1.0.4 10/17/2022 - Added a simple onboarding experience to give users a sense of what the app is about before they are required to login or create an account.
- Added third-party login methods, so that users may more conveniently login with their Apple or Google accounts. 1.0.3 10/14/2022 - Added "Suggested Studycards" at the beginning and end of each Activity, so that users can prepare or review material in an easier and better integrated way.
- Added Studycards for Translation, so that users can learn or review common indicator words and phrases.
- Updated "Payment Policy" policy page, so that payment information is more readily accessible and transparent.
- Added names to levels for Validity, Justification, and Inference, so that levels are more meaningful to users (especially in terms of their corresponding Studycard).
- Added "Play Again" button at the end of each Activity, so that users can relaunch an Activity without interrupting their flow. 1.0.2 10/03/2022 - Added more subscription options. 1.0.1 09/21/2022 1.0 09/18/2022