Logical Construct & Philosophy

Explore formal logic through interactive puzzles. Construct proofs, formalise paradoxes, reason like a philosopher or a mathematician.

Logical Construct is an educational puzzle app that makes formal logic genuinely playable. Instead of passively reading about reasoning, you actively construct valid proofs by applying the same inference rules used by logicians, mathematicians, and philosophers: Modus Ponens, Modus Tollens, Hypothetical Syllogism, Reductio ad Absurdum, and more.

Each puzzle gives you a few premises and a target conclusion. Your job is to build a chain of deductions, one rule at a time, until you reach the conclusion. By doing the proofs yourself, not just reading about them, abstract logical concepts become concrete, intuitive skills.

You'll progress through propositional logic, work with modal operators of necessity (□) and possibility (◇), and tackle advanced techniques like Conditional Proof and Reductio ad Absurdum. Classic philosophical arguments (the Paradox of Omnipotence, the Problem of Evil, Anselm's Ontological Argument, and Plantinga's modal version of it) become living frameworks for applying these principles. Reasoning that shaped two millennia of philosophy, now something you can practise on your phone.

WHAT'S INSIDE • 20 levels, 60 puzzles, from your first Modus Ponens to S5 modal logic • 24 inference rules organised into six categories: conditional, conjunction, disjunction, negation, biconditional, and modal • Step-by-step solution viewer that reveals the proof one move at a time: it shows you the path, it doesn't solve it for you • Truth tables for every propositional rule, with the row where all premises are true highlighted so you can see why the rule is valid • Live formula highlighting that shows which lines a rule will use • Subproofs with Fitch-style indentation: the natural way to learn Conditional Proof and Reductio ad Absurdum • First-launch tutorial that walks you through your very first deduction, plus dedicated intros for subproofs and modal logic • Atom legend on every puzzle: tap to see what each symbol stands for and read the puzzle as a story in plain language • Neumorphic design with colour-coded rule categories • Progress tracking with automatic level unlocking

WHO IT'S FOR Students strengthening their formal reasoning, philosophy enthusiasts curious about how arguments actually work, or anyone who enjoys a good puzzle that makes you think clearly.

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