an increase measured against a belt of inextensibility|
Expansion is a relative concept which implies a reference and can only occur relative to an assumed dimensional time-invariate.
Expansion is not an absolute intrinsic property of an entity any more than curvature, magnitude or happiness.
Consider evaluating the assertion... the balloon is expanding...
Once we have mutually agreed which entity is being pointed to... and that it is indeed a balloon...
then we can proceed to determine whether or not it is expanding.
Expansion can only be verified convincingly by comparison measurements.
A length dimension of the balloon... like the distance between its eyes...
must be compared over time with a standard invariate length.
A non-elastic belt around the guts of the balloon would serve splendidly as the reference.
Compare the distance between the eyes with the belt circumference and record the ratio.
Compare the distance again later and record the ratio.
If the ratio has increased then the immediate conclusion of a balloonist would be that the balloon was expanding.
Without a standard belt of inextensibility, determining the expansion or not of the balloon is less than straightforward.
With all the chosen ruler standards expanding, and our clever doppler radar machine expanding,
and our own brains and bodies expanding, and our information transmission medium light expanding,
and even our inflated cosmological theories expanding, the only way we can possibly ever know if the balloon was expanding
or not will be to phone someone on the outside who had an inextensible belt.
But our extra-cosmic contacts have notoriously unreliable lines of communication.
If everything in the cosmos is expanding without exception...
you, me, apples, rulers, light diffraction gratings, clocks,
stars, the space between stars, atoms, the space between atoms, etc...
there would be no means of verifying the situation.
The ratios of distances within the universe with respect to itself would remain the same, and suggestions of universal expansion...
or contraction for that matter... would be pointless.
The evidence of our terrestrial experiences is that complex existential systems are continuously exchanging energy,
and regions of those systems undergo expansions and contractions in response to those energy relocations.
The oceans and the atmosphere expand and contract, become hotter and cooler, and generally exhibit dynamic variation.
Geological systems, biological systems, social systems, are all characterised by growth and decay patterns.
Since almost everything we observe is either increasing or decreasing, it should not
come as a surprise if evidence confirms that we are in a region of the universe
which is expanding... but to suppose the entire universe is expanding, demonstrates no more insight than previous
human cultures who described the entire universe in terms of their local conditions.
As is usually the case, the speculations about the expansion of the
cosmos are distended primarily by dollars pumped into cosmologists bank accounts.
Once the economy
stops expanding and the discretionary funding dries up,
the expansion of the universe will slow to quite imperceptible levels.