I examine Andreas Osiander’s views on hypotheses. Osiander’s views are of more than just historical interest. I argue that Osiander draws attention to aspects of hypotheses that continue to deserve our attention. Osiander draws attention to both (i) evidential considerations and (ii) sociological considerations. I argue that both of these types of considerations have epistemic import. Osiander is also most clear about what instrumentalism entails. He thus provides some insight into the nature of instrumentalism as an account of scientific hypotheses and theories.