Fields of Research in Philosophy of Physics
My main areas of research are foundations of quantum mechanics and space-time structure, including the role and meaning of symmetries in physics.
Most of my recent work was related to my book Physical Relativity, O.U.P (2005) on the philosophy of relativity theory-mostly special relativity. There I defended the view (advocated by Lorentz, Pauli and Bell, inter alia) that relativistic kinematics are essentially dynamical in origin, arising out of the treatment of rods and clocks as 'structured' objects and thus involving the Lorentz covariance of all the fundamental non-gravitational interactions. I am also interested in the attempt to formulate gravitational and non-gravitational dynamics relationally, in the sense of the program of Julian Barbour.
My work on symmetries engages with current disputes concerning the appropriate formulation of spacetime and internal symmetries. It also involves a collaborative effort with Katherine Brading on the history and philosophy of Noether's theorems. My most recent work on the foundations of quantum mechanics deals with the so-called topological approach to identical particles, in which the characteristic phase factor determining Fermionic, Bosonic or intermediate behaviour is seen as a configuration space analogue of the Aharonov-Bohm effect.
My main interest is in the interpretation of space-time physics. I work on a number of topics that fall under this broad heading, including (i) the substantivalist--relationalist debate, (ii) the meaning and status of general covariance and background independence, (iii) Machian approaches to general relativity, especially Julian Barbour's approach, and (iv) dynamical approaches to spacetime structure.
My interests extend to a number of other related topics. These include (i) philosophical issues that arise in the context of quantum gravity, especially the recovery of standard background-dependent quantum theory, and (ii) the metaphysics of time, modality and identity.
I work on the foundations of quantum mechanics (including field theory), particularly the Everett or many-worlds interpretation. I also work on space-time theory, the discrete symmetries, and the foundations of statistical mechanics. My work in these areas leads me to a general view of metaphysics and its relation to physics which I am attempting to set down in a book. A key logical category, discovered by Quine, that plays an important role, is that of 'weak discernability'. It has figured in several of my recent papers (see my website or the Pittsburgh archive). It is the key to a broadly structuralist view of objects, as things between relations, consistent with the theories mentioned.