chris peck wrote:
we can just understand it in terms of our brains having different memories
and anticipations of the future at different points along our worldline.
I think that is necessary for an understanding of time, but insufficient.
What governs which set of memories and anticipations is being entertained?
The laws of physics, I suppose. And certainly time is not treated the same
way as spatial dimensions are by the laws of physics, but all of physics can
be understood in terms of the "block time" view, and relativity actually
seems to favor it.
Somehow, each set is individuated from the others, what process prevents
the whole set from striking one all together.
I guess the same thing that prevents events at different spatial locations
from all happening in the same place--events just have different locations
in spacetime. Do you accept the existence of timeless mathematical
structures like the Mandelbrot set, with different elements of this set
having different locations in the complex plane? If so, what's wrong with
the idea of our universe's spacetime and the events within it just being
another such timeless mathematical structure? Not that we *must* accept such
a view, but I don't see any logical problems with it.
Relativity poses severe problems for the idea that there is actually a
single "present moment" which is constantly moving towards the future in
some universal, objective sense.
True. Im not unaware of that and I find it a really difficult problem. Isnt
it the case that staggered 'nows' are caused by physical rather than
conceptual circumstances? Actually travelling at different speeds and so
on. How does this happen if 'now' is merely conceptual and completely
I don't really understand your question...it's not that "now" is completely
subjective, given a particular object moving inertially there is an
objective truth about how simultaneity is defined in that object's rest
frame. But the fact that different coordinate systems disagree about whether
two events have the same t-coordinate doesn't seem fundamentally different
from the idea that two spatial coordinate systems can disagree about whether
two objects have the same x-coordinate.