C-K design theory or concept-knowledge theory is both a design theory and a theory of reasoning in design. It defines design reasoning as a logic of expansion processes, i.e. a logic that organizes the generation of unknown objects. The theory builds on several traditions of design theory, including systematic design, axiomatic design, creativity theories, general design theories, and artificial intelligence-based design models. Claims made for C-K design theory include that it is the first design theory that:

1. Offers a comprehensive formalization of design that is independent of any design domain or object
2. Explains invention, creation, and discovery within the same framework and as design processes.