This essay reviews the origins of key concepts used in most global models. Philosophical preconditions for validity are examined. A framework for critically evaluating existing global models is suggested. A philosophy for global modeling is outlined. Global modeling is a much deeper enterprise than its critics seem to be aware. However, because global modeling lacks an academic or institutional home, key issues that have arisen with early global models are left essentially untouched. To critique global models or global modeling meaningfully, at least three perspectives are essential: those of science, philosophy, and practical application (praxis). A firm foundation for global modeling requires that its practitioners adopt an academic paradigm (i.e., university research institutes, schools and departments, a professional association, and a professional peer-reviewed journal). Global modeling is the only methodology capable of helping humanity to self-consciously envision itself and its environment in a time frame long enough and a scale large enough to provide an effective guide in its transition from a global to an interstellar species.