Discusses conceptual models of thought that have recently emerged to confront the conventional approaches to analysis and solution to complex environmental problems. In addition to a critical attack on the tradition of specialization and reductionism, several models are summarized that originated from ecology, cybernetics, and system theory. (BC)

States that constructivism is a theory of knowledge which asserts that knowledge is not primarily received, but actively built, and that the function of cognition is adaptive and serves the organization of the experiential world. Gives a brief history and discusses impact of the constructivist approach. (RT)