Husserl claimed that all theoretical scientific concepts originate in and are valid in reference to 'life-world' experience and that scientific traditions preserve the sense and validity of such concepts through unitary and cumulative change. Each of these claims will, in turn, be sympathetically laid out and assessed in comparison with more standard characterizations of scientific method and conceptual change as well as the history of physics, concerning particularly the challenge they may pose for scientific realism. The Husserlian phenomenological framework is accepted here without defense, and hence the present project is limited to the task of asking what can and cannot be accommodated within that framework on its own terms.