The philosophy and methodological assumptions of World3.

Models are typically developed and used to simplify otherwise overly complex processes or systems which are in need of analysis. The nature and implications of a world model constructed to better understand the long-term causes and consequences of world population and material production growth are described. While they are merely simple mental models based upon intuitive generalizations of observations of real-world events which fail to allow mankind to increase its understanding of the world. Complex social systems instead require that a variety of mental models be brought together and translated into a common language; all important implications are then determined simultaneously. Mathematical equations are best suited to describe such formal models. Based on system dynamics World3 is an example of this more ideal model form and combines elements of ecological and technological world views as well as theories derived from many traditional disciplines. It simplifies the complexity of the total socioeconomic system yet is more complex than mental models. Guidelines followed and results obtained in the early stages of formulating the model are described. Specifically the system is generally described; the models purpose in terms of the dynamic system behavior to be explained is precisely specified; the models time horizon is defined; and major elements necessary to represent the relevant aspects of the system are identified. Closing sections describe guidelines employed in the specification and preliminary testing of the World3 model equations. Model experimentation and results are presented in subsequent chapters and/or under separate cover.