The term "logic" is often used in many different ways. It is sometimes understood broadly as the systematic study of the principles of good reasoning. As such logic is not very different from critical thinking. But sometimes "logic" is understood more narrowly as what we might call "deductive logic". Roughly speaking, deductive logic is mainly about the consistency of statements and beliefs, as well as the validity of arguments. These are the topics we shall investigate in the following modules.

Formal logic is the study of logic using special symbols and clearly-defined rules of reasoning. They are very useful in linguistics, philosophy, artificial intelligence and mathematics. The tools of formal logic can also help us formulate ideas and arguments more precisely. In our web site we introduce two of the most basic systems of formal logic.

- Fun logic puzzles
- Knights and Knaves puzzles (382 of them!)
- The World's hardest logic puzzle Warning: It's really tough!

- A very good informal introduction: Graham Priest - Logic: A Very Short Introduction
- An introduction to formal logic. Used to be the standard textbook for first year logic students at Oxford: Wilfrid Hodges - Logic
- Harry Gensler - Introduction to Logic
- Very advanced: George Boolos - Computability and Logic
- Many advanced topics included: Theodore Sider - Logic for Philosophy
- A good textbook on formal logic that is available free online: http://tellerprimer.ucdavis.edu
- A good logic self-study guide (PDF): Teach Yourself Logic 2017: A Study Guide
- Entries on logic in the Stanford Encyclopedia of Philosophy - These are articles that discuss some of the main issues in the philosophy of logic. They are difficult!