Theory of knowledge (TOK) plays a special role
in the International Baccalaureate® (IB) Diploma Programme (DP), by
providing an opportunity for students to reflect on the nature of
knowledge, and on how we know what we claim to know.

It is one of the components of the DP core and is
mandatory for all students. The TOK requirement is central to the
educational philosophy of the DP. (ibo.org)