Critical reasoning emerges out of a balanced sense of the power and the frailty of serious thought. This perspective motivates the way I organize my courses: around awe-inspiring theories as well as the historical trends that both support and complicate them. I might begin a lecture by summarizing Malthus’s theory of the clash between the geometric growth of the population and the arithmetic growth of the food supply, but I always follow this summary with statistical evidence showing that humanity has definitively broken through the Malthusian ceiling. I want students to marvel at a world in which the majority of the population lives in cities and depends on others to grow their food. What made this world possible, historically? Organizing courses around such questions helps students understand the stakes of historical arguments.