I am a Tutorial Fellow in Philosophy, at Somerville College in the University of Oxford.
Most of my research is in the philosophy of physics.
I'm also a caver and explorer.
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| Email: | hgreaves [at] wildcats [dot] com |
| Mailing address: | Somerville College |
|
Oxford OX2 6HD
UK |
Email is the quickest and most reliable way to reach me.
My research is primarily in philosophy of physics.
Much of my recent research has concerned spacetime symmetries, with a particular focus on the CPT theorem. I have been exploring a little-known classical analogue of the CPT theorem, originally due to J S Bell. This classical result interests me because (i) it shows that, contrary to the general impression, there is nothing essentially quantum-theoretic about the CPT theorem (the CPT result follows rather trivially from Lorentz invariance, and hence applies can be derived in classical as well as in quantum Lorentz-invariant field theory); (ii) it allows us to pose and answer basic conceptual puzzles concerning the relationship between CPT symmetry and spacetime structure, in a framework that is much more conceptually and mathematically straightforward than that of quantum field theory.
Right at the moment I am puzzling about several more or less unrelated issues: the empirical significance of gauge symmetry, how to extend the classical CPT theorem to classical spinor field theories, and (most vaguely) whether there is a coherent metaphysical position in the vicinity of 'structuralism' that dissolves or sheds new light on foundational issues in physics.
Previously, I worked on the interpretation of quantum mechanics: specifically, the decision-theoretic approach to probability in the Everett (many-worlds) interpretation. One of the main prima facie difficulties with this interpretation is how, since (in some sense) all possible measurement outcomes actually occur, we can make any sense of the probabilistic language in which predictions of quantum mechanics are couched. For decades this problem seemed completely intractable, and has led many to abandon the interpretation. A conceptual breakthrough came in 1999, when David Deutsch suggested that one can understand Everettian probability in terms of rational decision-making. Deutsch's approach has been developed and clarified in several papers by (in particular) David Wallace; my project in this area has been to develop an alternative interpretation of the decision-theoretic programme, freeing it from one of its controversial philosophical assumptions (`subjective uncertainty'). (My Compass survey article provides a non-technical overview of the decision-theoretic programme.)