The direction of the flow of time is meaningless

I think I've sorted a lot of this stuff out, at least for myself.

There are two senses of time that we use - 1) The objectively observed reality between people of relative rates of processes, or a chain of shared events and 2) The personal subjective experience of change over time.

As others have said, time isn't defined well as a rate. It's a chronology of specific events. Something has to happen for any reference marker of time to be set and compared against and when you dig down far enough that event simply separates events before and after it, but has no magnitude in itself. Time only goes forward because it's measured by changes and even reversing a change is a change in itself. Only by creating an alternate extrapolation for the definition of time could you calculate negative values for changes over time.

Things might be best described as simply information over time. For example, if you were to witness a 1-D bitstream over time as 01110011100111001110.... you could correlate this bitstream with itself and extract the 2-D pattern of:

01110
01110
01110
01110
...

If you altered this pattern over time, you could create a changing 3 dimensional representation (2-D + time).

Along the same lines, we only experience a 2-D universe. All we truly know and can sense at any specific moment are surfaces. If I drew some dots on a piece of paper, they would simply appear as dots in a 2-D plane, but if these dots moved in a pattern correlating to the vertices of a 3-D cube, then the mind takes 2-D sensations, adds time and comes up with a 3-D image. Even taking a snapshot of the moon doesn't give 3-D information - it simply displays a surface and doesn't tell whether the moon is orbitting the Earth or on a collision course.

The universe is 2-D + time. Even gravity, which we would imagine as multiple 3-D + time sources truly only acts as a single force from a specific 2-D vector you could point toward (horizontal and vertical or latitude and longtitude) and even the amplitude is something that can only be determined over time, as it's only through time that acceleration operates. If you see a block of wood, you assume it's 3-D and can tap it to demonstrate waves propogate along the depth of it, but again we can only relatively instantly interact with the surface and the depth is something that's revealed only by time. Even if 50 scanning electron microscopes were watching the waves travel through this block, they'd simply be 50, 2-D + time representations of the same thing. Instead of envisioning time extending as a rigid absolute extending forward and backwards from the present, we all shared a 2-D + time universe, of which even the 2-D component takes time to sense ... time or more precisely, information over time may be all there is and the rest depends upon what correlations we extract from the chronology like distances and depth, and just as distances need a start and stop location to measure between, time exists only between discrete events as well. There's no way to distinguish between a long chain of little 'nothings' occuring very rapidly or a single big slow 'nothing' - time is a part of neither. It's instead a chronology of contrasts and rates of time are simply statistical ratios between occurances of separate events.

I always had a hard time understanding this but it finally started 'clicking' for me. Truly everything we know would seem most precisely described as simply a sequence of discrete events, that over time we correlate into an approximation of relationships, and correlating the distances between these give the appearance of dimensions. (2-D + time seems to best describe the objectively witnessable universe shared between people, though admittedly most people assume 3-D + time is the correct model, at least for denoting histories but there seems little evidence to me that a model of the universe able to describe various "here and nows" needs to include a universe that retains a history of all 3 dimensional events over time - our 3-D view of things already includes processes that create motion that only interact as surfaces (forces are 2-D + time and everything we know is an interaction between these) ... I admit it's still a bit hard to grasp but 2-D + time seems the correct description to describe the shared universe we experience, and the time component doesn't even need to be very "thick", in a sense, because it's largely generated deterministically so the time dimension could operate similar to a state machine ... with likely some unpredictability thrown in). For all the talk of 6, 10 dimensions etc ... maybe 2.5 dimensions or less (in a fractal sense) would work just fine.

Just like in that above bitstream example, you could take 1-D + time and correlate it into a line in 2-D, or alternately you could view it as a 1-D object of length 5, with a property of 01110 that exists throughout time. Either view could be valid, but claiming it's a 2-D + time bitstream seems unjustified because you'd need to arbitrarily pick some frame of it in which to call it a 2-D image and then claim that arbitrarily selected 2-D subsection has an additional time component. So yes, you could call it 2-D + time, but that's not an accurate representation of the real data received but an arbitrary mathematical extrapolation.

I recognize why mathematically 4 or more dimensions are referred to but these don't necessarily need to exist in any infinite sense in reality ... though I'm not saying they can't exist.

Sorry for rambling but I think people often get lost in the math and then envision reality according to it, whereas the math should be made to fit reality. I wanted to put down some of these insights and thank you for the replies also. Time is a tough subject and determining how to correlate data over time correctly is even tougher.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by SteveA</i>
<br />I think I've sorted a lot of this stuff out, at least for myself.

There are two senses of time that we use - 1) The objectively observed reality between people of relative rates of processes, or a chain of shared events and 2) The personal subjective experience of change over time.

As others have said, time isn't defined well as a rate. It's a chronology of specific events. Something has to happen for any reference marker of time to be set and compared against and when you dig down far enough that event simply separates events before and after it, but has no magnitude in itself. Time only goes forward because it's measured by changes and even reversing a change is a change in itself. Only by creating an alternate extrapolation for the definition of time could you calculate negative values for changes over time<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Part of the problem with any discussion attempting to discern the nature of time itself is the very fact that it's almost impossible to even begin to describe the process without referring to it using time-based references. Words like "rate", "change", "chronological", "succession" all are time words. Time is so fundemental to everything that even explaining it is difficult without trying to measure it with itself. Very challenging.

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"Regret can only change the future" -Me

"Every judgment teeters on the brink of error. To claim absolute knowledge is to become monstrous. Knowledge is an unending adventure at the edge of uncertainty." Frank Herbert, Dune 1965

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Dangus</i>
<br />
Part of the problem with any discussion attempting to discern the nature of time itself is the very fact that it's almost impossible to even begin to describe the process without referring to it using time-based references. Words like "rate", "change", "chronological", "succession" all are time words. Time is so fundemental to everything that even explaining it is difficult without trying to measure it with itself. Very challenging.

<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Time is nothing more nor less than the measurement of change. As subject 'X' changes from state #1 to state #2, subject 'Y' changes from state #3 to state #4 or as subject '1' changes from position #A to position #B, subject '2' changes from position #C to position #D. It is simple incremental differentiation - no different than measuring distance with a ruler, but instead of comparing an unknown length to a standard unit, you are measuring the change occurring within some procedure against the duration of some standard event - like a rotation of the planet or the vibration of a cesium atom.

Mathematically it is convenient to consider time as a 'dimension' but other than the physical changes it measures, it has no separate existence or reality of its own.