emergent gravity; philosophy of physics; principles of physics; philosophy of quantum gravity
Crowther Karen (2020), As below, so before: ‘synchronic’ and ‘diachronic’ conceptions of spacetime emergence, in Synthese
Crowther Karen, Linnemann Niels (2019), Renormalizability, Fundamentality, and a Final Theory: The Role of UV-Completion in the Search for Quantum Gravity, in The British Journal for the Philosophy of Science
, 70(2), 377-406.
Crowther Karen, Linnemann Niels S., Wüthrich Christian (2019), What we cannot learn from analogue experiments, in Synthese
Le Bihan Baptiste, Linnemann Niels (2019), Have we lost spacetime on the way? Narrowing the gap between general relativity and quantum gravity, in Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Phy
, 65, 112-121.
Crowther Karen (2018), What is the Point of Reduction in Science?, in Erkenntnis
Linnemann Niels S., Visser Manus R. (2018), Hints towards the emergent nature of gravity, in Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Phy
, 64, 1-13.
Crowther Karen (2018), Defining a crisis: the roles of principles in the search for a theory of quantum gravity, in Synthese
Menon Tushar, Linnemann Niels, Read James (2018), Clocks and Chronogeometry: Rotating Spacetimes and the Relativistic Null Hypothesis, in The British Journal for the Philosophy of Science
Crowther Karen (2018), Inter-theory relations in quantum gravity: Correspondence, reduction, and emergence, in Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Phy
, 63, 74-85.
Doboszewski Juliusz, Linnemann Niels (2018), How Not to Establish the Non-renormalizability of Gravity, in Foundations of Physics
, 48(2), 237-252.
LinnemannNiels, Interpretations of GR as guidelines for theory change, in Sauer Tilman, Beisbart Claus, Wüthrich Christian (ed.), Birkhäuser, Basel.
To articulate a quantum theory of gravity--a theory unifying quantum physics and general relativity--has remained an unfulfilled challenge in physics for almost a century. Proposals for how to approach the problem abound, but all research programs face major mathematical, physical, and philosophical obstacles. Recently, the frontrunners in the race to find the elusive theory--string theory and loop quantum gravity--have stalled in their progress and the field is disintegrating into myriad research programs pulling in divergent directions. No empirical data is available to guide the hunt in quantum gravity. The mathematical, physical, and conceptual disunity of quantum physics and general relativity renders the difficulty nearly insurmountable. One way to find guidance out of the quagmire is to revisit the very presuppositions of the enterprise, question the possibly tacit assumptions behind stalling research programs, and consider the alternatives that open up once some of them are dropped. This is precisely what the present project proposes to do. The fledging field of philosophy of quantum gravity is almost exclusively concerned with the philosophical foundations of the dominating approaches. We propose to leave the trodden paths in the hope to gain novel insights on the problem of quantum gravity. We will do this in two ways. First, we will step back to reconsider what precisely it would mean to succeed in articulating a quantum theory of gravity. This suggests a reevaluation of the basic physical principles such as unification, discreteness, background independence, general covariance, unitarity, correspondence, and holography, and a reconception of their justification and role in theory-building in quantum gravity. We aspire to developing an integrated account of candidate principles of quantum gravity. Second, we will examine the neglected--and iconoclast--possibility that gravity may not be a fundamental force, but instead the result of the collective non-gravitational interactions of fundamental degrees of freedom. This would degrade general relativity to an effective field theory, similar in status to hydrodynamics. We scrutinize two types of models in this 'emergent gravity' paradigm inspired by solid state physics and black hole thermodynamics, and evaluate to what extent their claims to generality can be upheld.Our project will be of great interest to a wider audience in philosophy. Quantum gravity, it is assumed--though this is not without detractors--, will eventually deliver a theory more fundamental than the current best theories, both of the fundamental constitution of matter (the standard model of particle physics), as well as of the large-scale structure of spacetime (general relativity). Hence, philosophers interested in the fundamental structure of the world will do well to pay attention to what happens in quantum gravity. The project is also of great interest to general philosophy of science, as it considers to what extent a methodology driven by principles can replace the usual empirical methods of science when these latter seem to become obtuse. To enter the fray and engage at short range in the scientific process of constructing a physical theory with deep implications for our conception of the world before the final theory gets inscribed into the textbooks for all to study is an exciting opportunity. By getting immersed in this process, we hope to contribute to this effort with our uniquely philosophical skill set and to draw valuable lessons for the larger fields of metaphysics and philosophy of science.