On 6 June 2015 at 11:26, Bruce Kellett <bhkell...@optusnet.com.au> wrote:
> LizR wrote: > >> This is true if events have an existence apart from maths. However, that >> is still being debated. Tegmark's "mathematical universe hypothesis" >> suggests that time and events are emergent from an underlying timeless >> mathematical structure. >> >> To take something that is (hopefully) less contentious, the block >> universe of special relativity already suggests something similar to this. >> In relativity, all chains of events are embedded in a space-time manifold, >> and hence causation comes down to how world-lines are arranged within this >> structure. >> > > This is not true. Causality is still a fundamental consideration in SR, > and that carries over into the basic structure of quantum field theory. > Even within the block universe model, the light cone structure of spacetime > is fundamental. The light cone encapsulates the fundamental insight of SR > that causal influences cannot propagate faster than the speed of light -- > the light cone is the limiting extent of causal structure. The laws of > physics consistent with this structure in SR and beyond are have a (local) > Lorentz symmetry, which preserves the causal structure between different > Lorentz frames. The distinction between time-like and space-like > separations of events is aa fundamental tenet of physical law. > > None of this contradicts what I said. All I am concerned with is that SR indicates that events are embedded in a 4D continuum. Describing how they're embedded doesn't change that. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
