[deleted]
Tom,
You wrote,
"A lot of fallacies here. First, your definition of motion does not imply change. "...change in space per change in time ..." is empty of physical content. It's not Einsteinian at all--one does not measure change in a space that is isomorphic for all observers (as special relativity informs us); one only measures change by the differences in relations among mass points."
You see it as "empty of physical content," only because you insist on defining the change of space in the equation of motion, as the change in the location of a mass point. If something isn't moving, if an object is at rest in an observer's rest frame, as time passes, you see no motion present.
However, we have no fundamental definition of a mass point. If we assume it is an electron, and try to describe it, we find an inherent contradiction. This mass point is charged, a point with no extent, yet it possesses angular momentum in the form of something called quantum spin that science has no clue how to describe. We have to hold it together with something, but not knowing what it could be, we just call the energy "Poincare stresses," and leave it at that, even though we know the thing should blow itself apart.
That sounds a lot more fallacious to me than the claim that the only known relation between space and time is reciprocal. The problems I see in these discussions always comes down to definitions, or the lack thereof. When I say "changing space," I don't necessarily mean "changing distance." The definition of motion includes changing distance, but it's not limited to it. When I say "changing time," I mean a succession of moments, of some duration. There is no way to measure space without a succession of moments, and no way to measure time, without a changing interval of space. That is, space and time don't have an independent existence, but are two, reciprocal, aspects of one component, motion, just as the numerator and denominator of a ratio are two, reciprocal, aspects of a rational number.
Given the numerator of a rational number, there's got to be a denominator and vice versa. We don't speak of numerators and denominators as if they were independent entities. They are simply part of the unified whole, different aspects of a rational number, like two sides of a coin.
While I will concede the point that there is no causal relation between time and entropy, one cannot measure entropy without a passage of time. In the same way, we wouldn't be able to measure the increased wavelength of light, without the notion of an increase of time. As far as the cosmic redshift is concerned, it seems as though you are at odds with established fact there.
But regardless, we must define motion in terms of units of accumulated space and units of accumulated time. If it were not so, there would be no spacetime to measure. The only way to measure spacetime points is to choose a point of reference in some observer's frame of space and time and start counting a change of space over a change in time in some direction. The 1D trajectory of some physical entity, such as a set of photons, to mark the change in a given direction is useful, but it doesn't characterize the motion completely, since the actual motion may be outward from the observer in all directions simultaneously, as observed in the case of receding galaxies.
In this case, if there are three galaxies, moving away from each other, this doesn't mean that there is only motion in three directions. No matter how many galaxies there are, they will all move away from each other. If they all explode and evaporate, the motion separating their locations doesn't cease, just because they did. In fact, if galaxies A, B and C are in a line, the direction of the motion separating them is indeterminate. An observer on B will observe A and C moving in opposite directions, while an observer on A will observe B and C moving away in the same direction, and an observer on C will observe B and A moving in the same, but opposite, direction reported by the observer on A.
Which observer is right? The truth is that they are all right, because the direction of expansion is in all directions simultaneously. Such motion is motion of the locations themselves, not the objects occupying the locations, and exists regardless of whether or not mass points occupy the locations.
Regards,
Doug