Humanity delights in spinning conceptual models of the world. These models, in turn, mirror their respective root metaphors. Three root metaphors--spiritual, organic, and mechanical--have dominated western thought. The spiritual metaphor runs from Plato, through Hegel, and connects with Montessori. The organic metaphor extends from Aristotle, through Darwin, and joins with Dewey. And the mechanical metaphor stems from Democritus, through Newton, and links with Skinner. The three metaphors have played a germinal role in western philosophy. They have also shaped the character of educational thought and practice. Which model to choose? Your choice will depend upon the purpose or aim you have in mind.