Discussion: Conceptual foundations of field theories in physics

This discussion provides a brief commentary on each of the papers presented in the symposium on the conceptual foundations of field theories in physic s. In Section 2 I suggest an alternative to Paul Teller's (1999) reading of the gauge argument that may help to solve, or dissolve, its puzzling aspec ts. In Section 3 I contend that Sunny Auyang's (1999) arguments against sub stantivalism and for "objectivism" in the context of gauge field theories f ace serious worries. Finally, in Section 4 I claim that Gordon Fleming's (1 999) proposal for hyperplane-dependent Newton-Wigner fields differs importa ntly from his previous arguments about hyperplane-dependent properties in q uantum mechanics.