Hi Ian,
Thank you for your reply.
"...To be clear, I take the non-absolute nature of time to be an empirical result so, to me, it's not using relativity to support relativity. ..."
I assumed that was the case. It is the answer adopted by theoretical physicsts. I am not one, however, this is the way I see it:
Yes clocks will measure different intervals due to distance from mass. They are not intervals of time; they are intervals in time. Everything occurs durring time. This is not evidence that time controls everything. It is evidence that the cause of a particular activity is changing. Is time is a cause of activity and does time control the rate of activity? To prove either of those possibilities we need to perform experiments on time? Experiments on clock's of any type is no more informative that experiments on any other activity in the vicinity of the measurements. GPS adds only more additional information about how physical activity varies with respect to distance from mass. Unless time is established as the cause of all of this activity, then time is not the subject of the measurements.
The time dilation equation is actually the t dilation equation. The t in physics equations is a measure in time (some duration of some physical activity) and not of time (as in a testable property in itself). All activity is measured with respect to a standard of activity. That standard can be chosen by virtue of its exhibiting as stable as practical cyclic activity. For example, if one wished to measure the rate of cyclic activity A, one would compare it to the standard for cyclic activity. Both of these cyclic activities are material in nature and are therefore subject to effects brought upon them by other material objects. In other words, they both are variable.
We use the name seconds for the unit of measurement in physics equations: however, in the most fundamental sense, the units of t should be referred to as cycles of the standard chosen. So, by measuring cyclic activity A against the standard cyclic activity B, The true fundamental form of the units for both of them is (#cyclesA)/(cycleB). The property of time is not shown to be affected by this action. All activity requires time to occur. The time taken is a duration in time simply because time is passing during the activity. Time itself is not a physical property that can be sliced up, contained, or molded into a new form.
"...But I am of the opinion that we have to rely on empirical results to at least some extent because we built technology out of this stuff and it's all got to work and be consistent. ..."
I think it is crucial to remain dependent upon empirical results as closely as possible and to use theory only when necessary to risk moving forward in analyses in the face of the unknown. That is why I first refer back to photons as our source of information. They tell us that particles of matter changed their velocities. If there is no change of velocity, then we receive no information. There has never been an experiment that included a change of velocity for either time or space. They just are not available for us to trap and experiment upon.
"...Regarding your fundamental quantities, I might agree with space and time, but I definitely don't agree with force, at least how it is presently defined. I might be inclined to agree if we found a "broader" definition that took into account non-interaction-related correlations. ..."
I use the word force in a generic form, meaning that anything that causes change of velocity is a force. Gravity is a force. If a change in position of one object causes a change in position of another object, regardless of whether or not it is faster or slower than the speed of light, then I think that indicates a force exists. I see no fundamental problem with allowing for this possibility. I see it as analogous to saying that the speed of light is a constant in free space. Any coordinated behavior acrossed the universe is evidence that something is controlled by a means that exists outside the limitations of the speed of light.
"...As for things like black holes, even Newton predicted them. But my point is that the empirical evidence of their existence seems irrefutable. See, I personally believe that theory works best when it is based on empirical results since, for better or for worse, that's the window through which we view the world. ..."
Newton's black hole and Eistein's black hole are very different. Einstein's relies upon the existence of spacetime. There is no evidence that either space or time are affected by the activities of matter. There is evidence that matter affects other matter and that matter and light both affect each other.
I guess this might be getting tedious for you. I appreciate your time. I will let you have the last word. You are the expert.
James