Jan Sprenger (Tilburg) gives a talk at the 9th Formal Epistemology Workshop (Munich, May 29–June 2, 2012) titled "The No Alternatives Argument" (joint work with Richard Dawid and Stephan Hartmann). Abstract: Scientific theories are hard to find, and once scientists have found a theory H, they often believe that there cannot be many distinct alternatives to H. But is this belief justied? What should scientists believe about the number of alternatives to H, and how should they change these beliefs in the light of new evidence? These are some of the questions that we will address in this paper. We also ask under which conditions failure to find an alternative to H confirms the theory in question. This kind of reasoning (which we call the no alternatives argument) is rather popular in science and therefore deserves a careful philosophical analysis.