steve_bank said:
Time is not a reality, it is a unit of measure.
Hi Steve, it's been a while since I've participated in any substantive thread on these fora, so it's refreshing and I appreciate your call for precision. While Speakpigeon's OP may have lacked specificity, I'm not sure that it is reduced to babbling by that lack. Maybe I was too generous in my assumptions that the OP referred to time in the common, colloquial sense of being the measure of when events take place or how long they take, typically measured using some cyclical thing like a clock ticking or caesium atoms oscillating. While absolute simultanaeity has been ruled out, it doesn't preclude relative simultanaeity, and that's what I thought we were talking about. Certainly, it has been shown that relative motion has effects on observations of time but I don't think that obviates the question as to whether time or its passage is a thing. Even though two observers in different inertial frames may disagree about the duration or order of events, and even though neither perspective takes precedence over the other, the observations aren't of something unreal or meaningless. The very fact that observers in different inertial frames might disagree about the order or duration of events, or agree upon them by taking their relative motion into consideration and agreeing on an arbitrarily preferred inertial frame of reference, suggests that both parties acknowledge that events have apparent sequences and duration. Furthermore, the fact that they could agree on a preferred reference frame, synchronize their clocks and successfully rendezvouz, means that consideration of time is not only meaningful but practically useful.
steve_bank said:
The word time is a loaded word.
As I mentioned in my initial response, I'm not aware of any language that doesn't fundamentally assume the existence and passage of time. Verbs, which are required of any complete statement (in English at least), are tainted with time. I predict that almost any statements intended to convey an idea of time as anything other than the common, colloquial understanding will be hamstrung by the language in which it is conveyed.
Speakpigeon said:
Strictly speaking, you don't observe motion. At any moment in time, you can only look at what is happening in that moment. Obviously, our senses suggest the reality of motion and indeed the reality of time. But, strictly speaking, perception doesn't "imply" anything.
I am not sure that I quite follow your meaning entirely, especially considering the way it is (probably necessarily) worded. I would contest that I, or anyone else, does observe motion but, I think your argument is that you can only observe a "moment" (I assume an infinitessimally short period of time) without reference to the preceding or subsequent moment and that our senses construct the sequence of events. The term "happening in that moment" seems inappropriate since nothing can be happening in no time, only things being. I think that, contrary to your statement, the apparent sensation of time not only suggests, but implies that the passage of time is a real thing. If there is more than one moment to observe and construct as the sense of time passing, then how else could those two moments exist unless they were in fact separated by a period of time.
Maybe, as you suggested and I mused earlier, time is like a fourth spatial dimension where two events that we would ordinarily describe as separated by time could be viewed by something with four dimensional perception as existing at the same time with separation along the fourth axis. However, I question whether it would be sensible to consider the same object separated on a time axis as having different identities at different positions in time. In any case, I don't think this negates our sensation of time as being reflective of reality.
bilby said:
Clocks do not remain synchronised, unless they share an acceleration frame.
I certainly wouldn't dispute this, however, clocks in the same inertial frame can be synchronized to a degree that is practical and of essential utility. I think, and please correct me if I'm wrong, that the opening question asks why synchronization would be possible at all if time were not real, not that absolute simultanaeity can be established. I believe that absolute simultanaeity has been more than adequately ruled out.
steve_bank said:
Imagine a closed box with a number of balls in it. I shake the box and relative positions change, in this case what does time mean?
If there can be two different states of the balls then that limits us to only a few options. There are two states, separated by time. There is really only one state and the second is somehow unreal, irrelevant or dissociated. Both states are real but not separated by time (a concept which, if true, I can't wrap my head around). Perhaps there are other options that I haven't considered?
fast said:
How much time is passing can often be measured by measuring its proxy, change, but if our world suddenly ceased to have change, it’s not time that stand stills but instead our ability to measure any change.
But would this really be true? Would time have any meaning in a changeless universe? My general position is formed from the opposite approach which seems to be presented in the OP; without time, how is any change (and more specifically, the synchronization of changes) explicable?
bilby said:
It's not only not obvious; It's not achievable. Two clocks in the same room are experiencing different accelerations due to gravity. Not measurably so, but different nonetheless. They will not stay synchronized. Clocks DON'T stay synchronized with each other. That's the answer to your question.
It's the same basic answer as to the question 'Why do coffee tables migrate eastwards in December?' - they DON'T.
Your question is based on a false premise. I understand what you mean. But you don't understand that you are describing an hypothetical situation that cannot exist, as though it were a normal and routine situation in need of an explanation. It isn't; so it doesn't. The appearance that it does is an artifact of your human experience, wherein the desynchronization is too small to observe under most circumstances.
I don't think anyone here has yet argued that absolute synchronization to an arbitrary degree is possible. I think the OP is asking why synchronization would be possible at all without time, not that synchronization could be perfect. For the purpose of discussing whether time is a thing, any degree of synchronization is worth discussing. We can definitely synchronize clocks to the point where two things can happen down to the minute, second, and even subsecond periods. We can do it very well in a shared reference frame and we can arbitrarily "correct" observations between two frames. If the existence of time, the apparent duration and sequence of events, were not a real thing, how could even gross synchronicity be achieved?
Thanks to all for the discussion. I doubt we'll solve the riddle presented but I think it's worthwhile to think about it carefully and share our thoughts.