EPUB and EPDF available Open Access under CC-BY-NC-ND licence. Economic theory relies heavily on the idea of rational action, but how are we to understand the empirical content of rational choice when we can only observe the outcome, but not what goes into making the choice? With contributions from Alan Kirman and Rod O'Donnell, Karl Mittermaier's posthumously published work establishes a new conceptual framework that will enable economic theorists to forge new paths of empirical analysis. Introducing readers to the work of a profound thinker who was not recognized in his lifetime, this book, featuring previously unpublished material, is poised to become a seminal text in the philosophy of social sciences.