A dilemma for the emergence of spacetime in canonical quantum gravity

The procedures of canonical quantization of the gravitational field apparently lead to entities for which any interpretation in terms of spatio-temporal localization or spatio-temporal extension seems difficult. This fact is the main ground for the suggestion that can often be found in the physics literature on canonical quantum gravity according to which spacetime may not be fundamental in some sense. This paper aims to investigate this radical suggestion from an ontologically serious point of view in the cases of two standard forms of canonical quantum gravity, quantum geometrodynamics and loop quantum gravity. We start by discussing the physical features of the quantum wave functional of quantum geometrodynamics and of the spin networks of loop quantum gravity that motivate the view according to which spacetime is not fundamental. We then point out that, by contrast, for any known ontologically serious understanding of quantum entanglement, the commitment to spacetime seems indispensable. Against this background, we then critically discuss the idea that spacetime may emerge from more fundamental entities. As a consequence, we finally suggest that the emergence of classical spacetime in canonical quantum gravity faces a dilemma: either spacetime ontologically emerges from more fundamental non-spatio-temporal entities or it already belongs to the fundamental quantum gravitational level and the emergence of the classical picture is merely a matter of levels of description. On the first horn of the dilemma, it is unclear how to make sense of concrete physical entities that are not in spacetime and of the notion of ontological emergence that is involved. The second horn runs into the difficulties raised by the physics of canonical quantum gravity
Keywords Spacetime   Emergence   Quantum geometrodynamics   Loop quantum gravity   Quantum superposition   Quantum entanglement   Non-separability   Structural realism   Local beables   Structural Realism   Metaphysics   Systems   Worlds   Time
Categories (categorize this paper)
DOI 10.1016/j.shpsb.2012.03.003
 Save to my reading list
Follow the author(s)
My bibliography
Export citation
Find it on Scholar
Edit this record
Mark as duplicate
Revision history Request removal from index
Download options
PhilPapers Archive

Upload a copy of this paper     Check publisher's policy on self-archival     Papers currently archived: 15,865
External links
Setup an account with your affiliations in order to access resources via your University's proxy server
Configure custom proxy (use this if your affiliation does not provide a proxy)
Through your library
References found in this work BETA
J. Ladyman (1998). What is Structural Realism? Studies in History and Philosophy of Science Part A 29 (3):409-424.

View all 22 references / Add more references

Citations of this work BETA
Daniele Oriti (2014). Disappearance and Emergence of Space and Time in Quantum Gravity. Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 46 (2):186-199.
Vincent Lam (2013). The Entanglement Structure of Quantum Field Systems. International Studies in the Philosophy of Science 27 (1):59 - 72.
Edward Slowik (2013). The Deep Metaphysics of Quantum Gravity: The Seventeenth Century Legacy and an Alternative Ontology Beyond Substantivalism and Relationism. Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 44 (4):490-499.

Add more citations

Similar books and articles
Gordon Belot & John Earman (2001). Pre-Socratic Quantum Gravity. In Craig Callender & Nick Huggett (eds.), Physics Meets Philosophy at the Planck Scale. Cambridge University Press 213--55.
Jeremy Butterfield & Chris Isham (1999). On the Emergence of Time in Quantum Gravity. In The Arguments of Time. Published for the British Academy by Oxford University Press 111--168.
Jonathan Bain (2013). The Emergence of Spacetime in Condensed Matter Approaches to Quantum Gravity. Studies in History and Philosophy of Science Part B 44 (3):338-345.

Monthly downloads

Added to index


Total downloads

36 ( #89,738 of 1,724,892 )

Recent downloads (6 months)

3 ( #210,933 of 1,724,892 )

How can I increase my downloads?

My notes
Sign in to use this feature

Start a new thread
There  are no threads in this forum
Nothing in this forum yet.