Interactive Logic Labs
Explore formal logic through interactive diagrams, rule checks, and experiments. Build arguments, test them, and see for yourself why some forms are valid and others only look that way.
Counterexample Hunter
Pick an argument form and hunt for the counterexample: set P and Q to true or false until the premises are true and the conclusion false, then put it into words.
Open LabThe Wason Selection Task
Four cards, one rule: which cards must you turn over? Three rounds of the most famous puzzle in the psychology of reasoning, and the logic behind it.
Open LabSyllogism & Venn Lab
Build any of the 256 categorical syllogism forms, check the seven rules, and watch the Venn diagram decide. Then draw the diagram yourself and test your instinct in “predict first” mode.
Open LabBelief Bias Self-Test
Judge sixteen syllogisms, then see whether believable conclusions swayed your logic, side by side with the classic research.
Open LabScope Lab: Quantifiers & Possible Worlds
Draw arrows and toggle possible worlds to watch “every x has some y” and “one y for every x,” or “necessarily if P then Q” and “necessarily Q,” come apart.
Open Lab