Courses

Applied Logic

Can you tell good reasoning from bad? Discover why the same logical puzzle is almost impossible in the abstract — and almost trivial in the right context.

The Wason Selection Task

Devised by psychologist Peter Wason in 1966, the selection task is one of the most replicated and debated experiments in the psychology of reasoning. You are shown four cards and a conditional rule of the form "If P, then Q." Your task: select the minimum set of cards to turn over in order to test whether the rule could be false.

It sounds straightforward. But decades of research show that most people — including highly educated adults — choose the wrong cards when the problem is stated in abstract terms. Present the same logical structure in a familiar real-world scenario and performance jumps dramatically. This is the content effect, and it is the central puzzle this course investigates.

How to play

  1. Read the conditional rule.
  2. Click the cards you think must be turned over.
  3. Press Check to see if you are right.
  4. Read the explanation, then move to the next version.

The key question is always: which cards could prove the rule false?

Try it yourself

Version 1 of 4 —

All done!

The key insight: The abstract and thematic tasks are logically identical — yet most people do far better on the thematic versions. This gap between formal correctness and intuitive reasoning is what this course is all about.

About This Course

Applied Logic introduces the fundamental tools of both formal and informal reasoning. Starting from the Wason Selection Task — one of the most studied problems in cognitive science — the course builds progressively from conditional logic and truth tables through to informal fallacies, argument structure, and real-world critical thinking. The aim is not just to understand logic abstractly, but to apply it: to recognise good arguments, expose bad ones, and reason more clearly in academic, professional, and everyday contexts.

Formal Logic

Conditional statements, truth tables, validity and soundness, propositional logic — the rigorous tools for evaluating arguments.

Informal Logic

Fallacies, argument mapping, cognitive bias, and the role of context — the practical tools for reasoning in the real world.

Course Units

  1. Propositions and Truth
  2. Arguments and Inference
  3. Deductive Reasoning
  4. Inductive Reasoning
  5. Conditional Logic
  6. Truth Tables
  7. Informal Fallacies I
  8. Informal Fallacies II
  9. Argument Mapping
  10. Applied Reasoning
10 units • Self-paced • Open access
Start Unit 1