The Arrow of Time

Meir Hemmo, Orly Shenker

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


We argue that if everything there is in the world is physical, then time has an objective direction. If the fundamental equations of motion are time reversal invariant we show that the direction of time cannot be explained by anything else in physics (e.g. the direction of processes in time) and therefore must be added to physics. We further argue that the direction of time gives rise to both the thermodynamic and the psychological arrows of time (whenever they exist), and that it is necessary in order to construct a meaningful Past Hypothesis in statistical mechanics.

Original languageEnglish
Title of host publicationBoston Studies in the Philosophy and History of Science
EditorsYuval Dolev, Michael Roubach
Place of PublicationCham
PublisherSpringer Nature
Number of pages10
ISBN (Electronic)978-3-319-22590-6
ISBN (Print)978-3-319-22589-0
StatePublished - 2016

Publication series

NameBoston Studies in the Philosophy and History of Science
ISSN (Print)0068-0346
ISSN (Electronic)2214-7942

Bibliographical note

Funding Information:
Acknowledgements This research has been supported by the Israel Science Foundation, grant

Funding Information:
number 713/10, and by the German-Israel Foundation, grant number 1054/09.

Publisher Copyright:
© 2016, Springer International Publishing Switzerland.


  • Direction of time
  • Entropy
  • Experience of the direction of time
  • Past Hypothesis
  • Second Law of Thermodynamics
  • Time-reversal invariance

ASJC Scopus subject areas

  • History and Philosophy of Science
  • Literature and Literary Theory
  • Anthropology
  • Social Sciences (miscellaneous)


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