The Theory of Knowledge (TOK) course is an interdisciplinary program designed to review and challenge knowledge. It involves the study of language, logic, ethics, knowledge, and truth.

The course examines the methods used to obtain knowledge in various subject areas. TOK looks at the trustworthiness of language as a means of communicating ideas and the reliability of perception as a means of observing the world. Dishonest and unreasonable arguments are distinguished from valid forms of argument.