The desirability of teaching usable knowledge in terms of inert knowledge is presented. A review of the literature covering knowledge structures, knowledge processes, and the link between knowledge and social interaction concludes with an outline of a tentative model of the knowledge system. Implications for second language instruction are also offered. It is suggested that inert knowledge in second language instruction can be linked to at least three sources: absence of authentic experiences; inaccessibility to knowledge; and apathy in the sense of a lack of self-initiated goals. For students to develop usable knowledge, they must have classes that are complex and open, and that direct students to other complex, open experiences. Contains 38 references. (LB)