Do the Laws of Physics Forbid the Operation of Time Machines?

Synthese 169 (1):91 - 124 (2009)
Download Edit this record How to cite View on PhilPapers
Abstract
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
PhilPapers/Archive ID
WTHDTL
Revision history
Archival date: 2016-12-13
View upload history
References found in this work BETA
Counterfactuals.Lewis, David K.
Laws of Nature.Carroll, John W.
On the Emergence of Time in Quantum Gravity.Butterfield, Jeremy & Isham, Chris

View all 8 references / Add more references

Citations of this work BETA
Time Machines.Manchak, John Byron

View all 9 citations / Add more citations

Added to PP index
2009-01-28

Total views
455 ( #5,421 of 38,991 )

Recent downloads (6 months)
12 ( #27,905 of 38,991 )

How can I increase my downloads?

Monthly downloads since first upload
This graph includes both downloads from PhilArchive and clicks to external links.