Do the laws of physics forbid the operation of time machines?

Synthese 169 (1):91 - 124 (2009)
We address the question of whether it is possible to operate a time machine by manipulating matter and energy so as to manufacture closed timelike curves. This question has received a great deal of attention in the physics literature, with attempts to prove no-go theorems based on classical general relativity and various hybrid theories serving as steps along the way towards quantum gravity. Despite the effort put into these no-go theorems, there is no widely accepted definition of a time machine. We explain the conundrum that must be faced in providing a satisfactory definition and propose a resolution. Roughly, we require that all extensions of the time machine region contain closed timelike curves; the actions of the time machine operator are then sufficiently “potent” to guarantee that closed timelike curves appear. We then review no-go theorems based on classical general relativity, semi-classical quantum gravity, quantum field theory on curved spacetime, and Euclidean quantum gravity. Our verdict on the question of our title is that no result of sufficient generality to underwrite a confident “yes” has been proven. Our review of the no-go results does, however, highlight several foundational problems at the intersection of general relativity and quantum physics that lend substance to the search for an answer.
Keywords General relativity  Time travel  Time machines  QFT on curved spacetime  Causality  Closed timelike curves
Categories (categorize this paper)
DOI 10.2307/40271293
 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: 16,667
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
John W. Carroll, Laws of Nature. Philosophy and Phenomenological Research.
Frank Arntzenius, Time Travel and Modern Physics. Stanford Encyclopedia of Philosophy.

View all 9 references / Add more references

Citations of this work BETA
Joachim Pfarr (2010). Closed Timelike Curves—Time and Again. Foundations of Physics 40 (9-10):1326-1332.
John Byron Manchak (2014). Time Machines. Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 48:124-127.
Cord Friebe (2012). Twins' Paradox and Closed Timelike Curves: The Role of Proper Time and the Presentist View on Spacetime. [REVIEW] Journal for General Philosophy of Science / Zeitschrift für Allgemeine Wissenschaftstheorie 43 (2):313-326.

View all 7 citations / Add more citations

Similar books and articles

Monthly downloads

Added to index


Total downloads

114 ( #25,380 of 1,726,249 )

Recent downloads (6 months)

24 ( #37,511 of 1,726,249 )

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.