Instants in Physics: Point Mechanics and General Relativity

  • Domenico GiuliniEmail author
Part of the On Thinking book series (ONTHINKING, volume 4)


Theories in physics usually do not address “the present” or “the now”. However, they usually have a precise notion of an “instant” (or state). I review how this notion appears in relational point mechanics and how it suffices to determine durations—a fact that is often ignored in modern presentations of analytical dynamics. An analogous discussion is attempted for General Relativity. Finally we critically remark on the difference between relationalism in point mechanics and field theory and the problematic foundational dependencies between fields and spacetime.


Mass Point Point Mechanic Inertial System Spatial Rotation Absolute Space 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



I sincerely thank Albrecht von Müller and Thomas Filk for several invitations to workshops of the Parmenides Foundation, during which I was given the opportunity to present and discuss the material contained in this contribution.


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© Springer International Publishing Switzerland 2015

Authors and Affiliations

  1. 1.Institute for Theoretical PhysicsLeibniz University HannoverHannoverGermany

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