Temporal Presentness and the Dynamics of Spacetime

The purpose of this paper is to pick up the threads of a debate about the ontology of becoming in spacetime that was triggered by a provocative article published by Nicholas Maxwell in 1985. This debate is itself merely a recent episode in a long dialogue that goes back at least as far as the time of Parmenides and Heraclitus (Savitt 2001). Here is the question around which this debate centres: is change or becoming the distinguishing feature of the natural or physical world, as suggested obscurely by Heraclitus and argued at length by Aristotle? (See Robinson 1987, Furley 1967, and Aristotle’s Physics, in, e.g., McKeon 1941.) Or is our usual uncritical belief in the reality of change the product of some sort of perceptual illusion or intellectual error, as believed by Parmenides and a small host of recent authors such as Gödel (1949) and Julian Barbour (2002)? I won’t be able to solve the whole of this momentous problem here. However, I intend both to set aside a few unwarranted assumptions which have for a long time dogged our thinking about the puzzle of becoming, and to assemble some tools which should aid in finding a solution to it. In particular, I will argue that we can do much better than is usually supposed in identifying structures which can both “live” within Minkowski spacetime and represent objective becoming. I shall also discuss whether such structures would necessarily contradict the Principle