Change without change, and how to observe it in general relativity

Research output: Contribution to journalArticle

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Abstract

All change involves temporal variation of properties. There is change in the physical world only if genuine physical magnitudes take on different values at different times. I defend the possibility of change in a general relativistic world against two skeptical arguments recently presented by John Earman. Each argument imposes severe restrictions on what may count as a genuine physical magnitude in general relativity. These restrictions seem justified only as long as one ignores the fact that genuine change in a relativistic world is frame-dependent. I argue on the contrary that there are genuine physical magnitudes whose values typically vary with the time of some frame, and that these include most familiar measurable quantities. Frame-dependent temporal variation in these magnitudes nevertheless supervenes on the unchanging values of more basic physical magnitudes in a general relativistic world. Basic magnitudes include those that realize an observer's occupation of a frame. Change is a significant and observable feature of a general relativistic world only because our situation in such a world naturally picks out a relevant class of frames, even if we lack the descriptive resources to say how they are realized by the values of basic underlying physical magnitudes.

Original languageEnglish (US)
Pages (from-to)381-415
Number of pages35
JournalSynthese
Volume141
Issue number3
StatePublished - 2004

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Values
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Cite this

Change without change, and how to observe it in general relativity. / Healey, Richard A.

In: Synthese, Vol. 141, No. 3, 2004, p. 381-415.

Research output: Contribution to journalArticle

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