We have a built in preconception of what Time is. We instinctively believe that there is some separate Phenomenon in Physics that we call Time. We believe that this Time Phenomenon is continuously running and always has been running in the background of everything that happens in the Universe. But this is a mistaken Belief and has been disproved by modern theories of Physics and especially by Special Relativity and by Quantum Field Theory. These theories have shown that Time is nothing more than Relative relationships between Objects and Processes. There is no Absolute Time. The Time that we use is not Absolute Time, but rather it is always relative to some Reference Physical Process. References are things like the Number of rotations of the hand on a mechanical Stop Watch, the Number of Rotations of the Earth on its axis, or the Number of Oscillations of a Cesium Atomic Clock. Each of these References will have their own accuracy specifications with the Cesium Atomic Clock being the most accurate. There are new Optical Clocks coming on line that are supposedly more Accurate than the Cesium Atomic Clock, but I will stick with the decades "Tried and True" Cesium Atomic Clock for this discussion. Logically, Science has used the Cesium Atomic Clock as the Reference for all other References. But the Cesium Clock is just a Physical Process, so we have all the other References being Relative Processes to the Cesium Atomic Clock Process.Philosophy Explorer wrote: ↑June 29th, 2014, 11:24 am Several threads about time have run. Yet we haven't gotten down to the nitty gritty, does time exist? Makes no sense to try to define time with measuring devices like clocks or calendars without first determining if time exists because if it doesn't exist, then with or without those measuring devices (including calendars), we may be wasting our time trying to define time on the basis of measuring devices and time-explicit and time-implicit equations may have no backbone to them if we don't know whether time exists.
A closely related question to the topic title is whether abstract time is objective? Because if so, we may never know the true nature of time. Now I turn the floor over to you.
PhilX
The upshot of all this is that Science does not use or know how to measure any kind of Absolute Time Phenomenon. It is always the Relative behavior of Physical Processes. This is the key to understanding that there is actually no such thing as an Absolute Time in Science or in the Universe. Science has discovered that Time as we think of it does not Exist. The Relative Time between Physical Processes is completely Local to the Physical Processes themselves. So we can say that before the Big Bang when there was supposedly no Matter, no Energy, and no Space, that there could not be any kind of Relative Time that was even Possible. Therefore, there was no Infinite Past, no Million Year Past, and not even a One Second Past, before the Big Bang. We actually should not even call the Relationship between Physical Processes, Relative Time. It is just a Relationship of the relative Numbers that are counted by the References. We can take the next step in this analysis and say there is no such thing as Time without specifying Absolute or Relative. A disappointing thing about the Non Existence of Time is that there is no possibility of Time Travel because there is nothing to go Back in and nothing to go Forward in.
Now let's consider Time from a Special Relativity point of view. First of all, Time is Not the Fourth Dimension of Space in spite of what the Science Snake Oil book writers say. Time plus the three dimensions of space form a mathematical four dimensional Manifold. Time is always given the index 0, and the three indexes of Space are given as 1, 2, and 3. If Time was considered to be the Fourth Dimension it would have been given an Index of 4 when they first formulated the equations. Time is simply a parameter that describes a particular behavior of Physical Matter. One of the most important results of Special Relativity is that Time slows down in a moving Frame. Even Cesium Atomic Clocks slow down. So a Cesium Clock on board the Space Station will run slower than a Cesium Atomic Clock on the ground. The knee jerk reaction to this is to say Time has slowed down. But all we know is that the Cesium Atomic Clock on the Station will register a smaller Number of Oscillations than the same Atomic Clock on the ground. But this only means that the Cesium Atomic Oscillations are slowed and it says nothing about what some Time concept is actually doing. It is the Relationship between the Number of Oscillations on the Station with the Number of Oscillations on the ground that is important. It is results like this that forced Scientists to realize that there is no Absolute Time Clock driving the Universe. If there was, then it would be impossible for Time to slow down on the Station and not on the ground. They realized that Time was not an independently Real Phenomenon that exists in the Universe. Time is always the result of Relationships between different Physical Processes. Without Physical Processes, Time does not even make any sense.
