Physics at its best even without calculations

Vesselin Petkov, 3 January 2017

Minkowski Institute, Montreal, Canada

If Minkowski had a chance to look (from the higher reality of his “die Welt,” i.e., spacetime) at the research strategy of the Institute named after him, I hope he would be delighted to see that along with his own way of doing physics (exploring the internal logic of the mathematical formalism of physical theories) and Einstein’s analyses of thought experiments, the strategy also fully exploits Wheeler’s “first moral principle” [1] – “Never make a calculation until you know the answer.”

I think this principle is enormously powerful when dealing with issues such as (for example):

  • The status of rotation in spacetime physics (not in general relativity, where the old 3+1 way of thinking is still allowed to try to complicate things). The issue of rotation is clear in spacetime (no calculations needed): it is the planets that orbit the Sun because their worldtubes are helixes around the worldtube of the Sun.
  • Conventionality of simultaneity – no calculations are needed to demonstrate that it is a matter of convention (as Einstein held) which events of spacetime are regarded as simultaneous (the fact that simultaneity is a matter of convention implies that the one-way velocity of light is also a matter of convention, which is self-evident in spacetime physics, where light is adequately represented by null geodesics; one-way velocity of light is a notion in the old 3+1 way of thinking). Any claim that simultaneity is relative but not conventional amounts to a contradiction in terms: there is no objectively privileged class of simultaneous events (due to relativity of simultaneity), but there is an objectively privileged class of simultaneous events (due to the non-conventionality of simultaneity).

References
1. E.F. Taylor, J.A. Wheeler, Spacetime Physics, 2nd ed. (W.H. Freeman & Company, New York 1992), p. 20

Advertisements