No, what is being measured is the passing of time, which is better described as the rate of such changes. The "rate" requires relations between changes themselves, not relations between objects, but relations between changes.. — Metaphysician Undercover

Maybe so. However, it still comes down to changes and changes are what is observed in the objects.

The objects and changes in them are observed on the basis of sensory perception such as color. The changes are changes in color, etc. as perceived by the mind.

And this seems to bring "time" very close to subjective experience.

One very wise person once told me, look at life one way (the bright side) and life is too short and look at life another way (the dark side) and life is too long. Life, it appears, is just another name for time. How can something (life = time) be both too short and too long?! This is about what people call subjective time and its length/duration seems to depend on whether one's having fun or one's feeling the blues among other things probably. In essence, if a man lives for 90 years, if he were happy, he'd feel it to be less than 90 and if he were, unfortunately, sad the same 90 years would feel more than 90. The only real way subjective time makes sense (less than 90 years or more than 90 years) is if objective time were itself real (90 years) as a reference point or comparison. Which comes first though? Subjective or objective time? Whether time is real would depend on the answer to that question, no? After all objective time implies time isn't an illusion, it's real.

That's certainly one way to look at it. I think Whitehead is instructive here:

Whitehead makes quite explicit the fact that his theory of space-time structure differs in two major respects from the Newtonian theory. First, the theory of space-time structure in the Whiteheadian cosmology is a relational theory as opposed to the "receptacle-container" theory in the Newtonian cosmology (PR 108f, 441). Space-time structure concerns relations between and sustained by the actual occasions of the universe; it is not an actual thing in which the real events of the world occur. Second, the extensive continuum, of which spatiotemporal extensiveness is a more specific determination, is a "real potential" factor of thc universe in the Whiteheadian cosmology as opposed to absolute space and absolute time continua as real and actual things comprising the universe in the Newtonian cosmology (PR 113f; cf. 101-06). The coming-to-be of present actual occasions actualizes -- specifically, spatializes and temporalizes -- an extensive order for the universe. These two points will be referred to again as this investigation concludes.

https://www.religion-online.org/article/whitehead-and-newton-on-space-and-time-structure/

That is, space-time as a description of relationships between point events, as opposed to a real container.

Thanks for the link. Yes, I think Whitehead is making an important point. We can't stay fettered to Newtonian ideas for ever. We need to explore new possibilities and perspectives. It isn't just time that progresses, we change and evolve too. Intelligence is never static, it is always full of new ideas and ready for new experiences. In any case, the subjective aspects of experience are as important if not more so than the objective ones.

Imagine a Mr. S who's, for some reason, always blindfolded. On Monday, he's taken to a room and his blindfolds are removed. He looks around the room, no clock, no calender, the room is sparsely furnished. He makes a mental note - he has a photographic memory - of all the objects, their color, shape, size, position, and so on.

Mr. S is blindfolded again, taken out of the room and kept in this state until Wednesday. On Wednesday, Mr. S is taken back to the room and his blindfolds are removed. He sweeps the room with his eyes and comes to the realization that nothing has changed about the room - every object is exactly how and where it was on Monday.

Insofar as Mr. S and this room is concerned, Mr. S can't distinguish it's still Monday (no time has passed/time is an illusion) and no, it's Wednesday (time has passed/time is real). If Mr. S is unable to tell the difference between real time and illusory time, the distinction is without a difference i.e. real time = illusory time. Case closed? :chin:

If time is an illusion — SteveMinjares

reality is one giant eternal clock