Lamaya, Sichuan, China, 2024
Publications
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Nothing Matters. Forthcoming in Philosophy of Science
Winner of the Mary Hesse Award 2024
Abstract: One challenge to relationism in General Relativity is that the metric field is underdetermined by the stress-energy tensor. This is manifested in the existence of distinct vacuum solutions to Einstein's field equations. In this paper, I reformulate the problem of underdetermination as a problem from vacuum solutions. I call this the vacuum challenge and identify the gravitational degrees of freedom (associated with the Weyl tensor) as the "source" of the challenge. The Weyl tensor allows for gravitational effects that something outside of a system exerts on the system. I provide a relationist response to the vacuum challenge.
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Are Symmetry Principles Meta-Laws?. Synthese 205, 223 (2025).
Abstract: Noether’s first theorem demonstrates that continuous symmetries give rise to conserved quantities. This fact tempts many to hold that symmetry principles explain conservation laws. Yet there is a puzzle: the derivation goes both ways. Why does symmetry explain conservation when the derivation is bidirectional? Lange (2007, 2009) provides an answer: symmetry principles are meta-laws, and meta-laws explain first-order laws just as first-order laws explain facts. Using a “non-standard” Lagrangian, Smith (2008) claims that conservation of angular momentum can hold without rotational symmetry, providing a counter-example to Lange. In this paper, I show that Smith’s non-standard Lagrangian fails to serve as a counterexample. However, that doesn’t leave Lange’s account unchallenged. I argue that the debate between Lange and Smith ultimately revolves around an ambiguity which, once clarified, leads to a dilemma. Which symmetry principle explains? Is it the symmetry of the action or the symmetry of equations of motion? If the former, then the symmetry is no more stable than conservation laws. Hence, we lose the desired explanatory direction. If the latter, the symmetry lacks explanatory relevance and fails to exhibit greater stability than conservation laws. However one disambiguates ‘symmetry’, it remains mysterious why symmetry principles explain conservation laws.
Works in Progress
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Why Not a Gravitational Perpetual Motion Machine?
Winner of the Clifton Memorial Prize 2025
(Email for draft)
Abstract: This paper examines longstanding concerns about gravitational energy and asks what it takes to rule out perpetual motion machines in General Relativity (GR). The answer is subtle. GR resists familiar assumptions behind conservation: there is no gravitational insulator, and defining an isolated system depends on asymptotic flatness. While the covariant conservation of stress-energy always holds, it offers no dynamical insight. Generic spacetimes lack Killing vectors, and stress-energy pseudotensors are non-tensorial and non-unique. To clarify the situation, I distinguish energy conservation — which concerns matter fields alone — from energy balance, which tracks exchanges between matter and gravity. Two claims follow. First, energy balance has genuine explanatory value. Second, rejecting gravitational energy altogether threatens our ability to rule out pathological scenarios. To avoid this, we must “make up a story” — a careful one — about gravitational energy.
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Chien-Shiung Wu: Breaking Parity Against Disparity
(Email for draft)
Abstract: This paper examines Chien-Shiung Wu’s scientific achievements and overlooked activism, situating her work within the socio-political contexts of 20th-century China and the United States. Wu was a pioneering figure: the first woman to join the physics faculty at Princeton, the first female tenured professor of physics at Columbia, and the only Chinese scientist in the Manhattan Project. Her 1957 experiment demonstrating parity violation remains a milestone in physics, yet her exclusion from the Nobel Prize highlights persistent structural barriers. Organized chronologically, the paper examines three phases: her migration and wartime work, the development and institutionalization of the Wu experiment, and her activism for equal opportunity at Columbia University. Wu’s story raises broader questions about feminist standpoint epistemology in physics, and about how structural inequalities shape scientific knowledge in the era of post-war "big science".
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Approximation Methods in General Relativity
(It's about Post-Newtonian and weak-field expansions! Ask me about it!)