The value and function of theoretical knowledge is an important and disputed issue, which has received surprisingly little scholarly attention. I attempt to clarify the notion of theoretical knowledge and examine its general relationship to learning. Theoretical knowledge is not necessarily distinguished by any particular content; the adjective “theoretical” can just as well signify a particular methodological approach or a way of dealing with a topic, including the way it is conceptualized. I further argue that theoretical knowledge can be merely (...) implicit and non-propositional. Though I reject a radical constructivist view, according to which knowledge acquisition consists in socialization, it must be admitted that socialization and the acquisition of theoretical knowledge do turn out to go closely hand in hand, inasmuch as theoretical knowledge is often a precondition of successful socialization. Concepts, principles, models and symbolic systems support the acquisition of both theoretical and other kinds of knowledge, but also help the learner to find her way about in an environment that is already formed by theories and conceptual understandings. Theoretical knowledge is both a learning instrument and a tool for navigation. (shrink)