In my current book project, Aphoristic Science: Speculative Ambiguity in Nineteenth-Century American Ecology and Psychology, I integrate scholarship in literature, philosophy, and science to identify a stream of aphorsitic thought that permeated American scientific prose. I focus on an interconnected group of American transcendentalists and pragmatists—Ralph Waldo Emerson, Henry David Thoreau, Emily Dickinson, William James, and W. E. B. Du Bois—who use the aphorism to engage readers in an unending process of interpretation. This “centrifugal” style encourages readers to continue a process of inquiry that spirals outward in new and creative directions. In defining the aphorism, I turn to the German-language tradition of Aphorismus (as distinct from Sentenz: the “sentences” or maxims, especially of the French moralists) to identify in the form an inherent evasiveness and ambiguity. Along the way, I draw on the extensive history of the aphorism—from the medical writings of Hippocrates to the scientific aphorismoi of Francis Bacon—to situate the form among science studies, affect theory, and a wide range of transnational theories of the aphorism.