Chalky wrote:

This is a semantic argument not a physical one.

No, it's not. The argument is entirely a physical
one. You don't see it because you are using a
failing intuition for the problem.

It is true that the distance to the big bang is
~13.7 billion lyr in all directions, but this does
not mean that the bb had a diameter of ~37.4
billion lyr, 13.7 billion yr ago.

That's not a useful argument, nor is it required.

Try to be a bit more alert to the sheer simplicity
of the situation.

The light (and _any other_ form of signal) from the
farthest observable universe, _by definition_, just
reached _us_.

The problem is spherically symmetrical.

Thus, regardless of _anything_ happening in between,
by sheer symmetry, the light from the farthest
observable universe "in front of us" has _not_ yet
had time to reach the farthest observable universe
"in back of us".

Elsewhere, you make arguments in terms of the ideal
gas law, but those arguments fail for exactly the
same reason: no mechanism exists, absent initial
propinquity, for communicating to the farthest
observable universe along one radius of the diameter
"from here" the _gas pressure_ of the farthest
observable universe along the opposite radius, so
there is no reason for the two pressures to resemble
one another _at all_, so any argument based on them
being spherically symmetrical fails from the outset.

The problem is perfectly general, for _any_ physical
constant: you can't get the information that makes
things smooth from one end of that diameter to the
other end of that diameter in the existing lifetime
of the observable (and thus from our point of view
"communicating with us") universe, absent arguments
that said diameter was at one time small enough that
considerations of propinquity allowed that
communication to occur and the observed smoothness
of the resulting CMBR (or of anything _else_ you
claim to be spherically symmetrical like the CMBR
is) to be other than coincidental.

Occam's razor then dismisses such claims of the CMBR
being spherically symmetrical and smooth "by
coincidence".

Quantum valeat.

xanthian.