This class explores how science and scientists work with the invisible, unseen, or unseeable elements of our world. We will examine how scientists convince themselves that these unseen things, such as atoms and molecules, are real. Many things cannot be seen or held in one’s hand, but scientists claim to have detected and to understand them. We ask probing questions about what it means to “see” or “observe” the world around us, and grapple with the basic question of how we gain scientific knowledge at all. Topics include telescopes and microscopes, atomic theory, the unconscious and psychoanalysis, human consciousness and intelligence, dark matter, and the nature of objectivity. We will pay special attention to how scientists are trained to see in particular ways, and how culture and worldview can shape, restrict, or enhance the way we observe. Readings include Galileo, Ernst Mach, Henry Adams, Stephen J. Gould, Peter Galison, T.S. Kuhn, Freud, Edward Tufte.