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.
Bruce
Presumably the arrangement has abstract reasons
(i.e. what we call the laws of physics, whatever they turn out to be).
So even in SR, causality in effect takes a back seat, becoming the
result of how observers are embedded in a "timeless" structure. Of
course in this case, time still exists as a dimension, as it was in
Newtonian physics. But even in Newtonian physics, Laplace imagined the
past and future would be "already there" as far as a sufficiently
godlike intellect was concerned.
So Newton and Einstein imagined that events were embedded in a physical
structure, but that they were "already there" in the sense of being
emergent from the laws of physics plus initial conditions.
ISTM that moving causation into a purely abstract realm is just one more
step in this process, and a logical one (though obviously one that needs
to be tested against reality).
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