This paper discusses the utility of a general systems theory paradigm for psychology. The paradigm can be used for conceptualizing such complex phenomena as change over time in living systems, person-society interactions, and the epistemology of multiply determined changes. Consideration is also given to applications of the approach to developmental research on aging and Piagetian postformal operations. The discussion indicates characteristics and core themes of general systems theory, as well as some system functions that are present in all systems. Tables supplementing and summarizing the discussion delineate (1) "patterns of systematic system change over time," (2) system characteristics that permit and retard change, and (3) what systems theory teaches about personal change. Other materials cover the systems involved in relativistic thought, and the balance between potential and order in a living system. (RH)