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Does Time Really Exist?

  1. Mar 16, 2009 #1
    Hello All,

    I've read through a couple of forum posts on time but didn't find what I was looking for.

    I've come to the conclusion that time doesn't actually exist and doesn't need to. However I'm always open for opposing points and would rather have a complete picture, even if I'm wrong.

    My thoughts are this --

    Time is required, even if it doesn't exist, to measure how "fast" something changes. Instead of time there is only persistent change. Change can happen "faster" or "slower" by comparing it to something else that changes, but changes extremely consistently. Generally these are Atomic Clocks. However if you put one of these Atomic Clocks near a binary star (imagine it isn't completely destroyed, etc) then that doesn't work anymore. I believe time needs to be standardized. E.g. theorize how an Atomic Clock(or replace with a better standard) would operate in the minimum(no external force, gravity, etc) and maximum(black hole, big bang, etc) environments. So essentially all there is is either faster or slower change, measured by another independent object. This also makes time travel impossible, which logically wasn't possible to begin with(grandfather paradox, etc). In conclusion I believe time is essentially the same as distance, temperature, etc. It is used to measure an aspect of change in a way humans can understand.

    On a side note...
    One of my major questions is, why is time required for existence? I still have not seen a good argument for this, mainly just people saying that without time the universe would not exist but that time can exist without the universe. Is this just an "je ne sais quoi" argument?

    Any input is appreciated.

  2. jcsd
  3. Mar 16, 2009 #2
    Time seems to be inexorable from the idea of any "change" taking place. I don't think it makes a whole lot of sense to talk about a universe where time doesn't exist because that is something that would be entirely impossible for a human to experience. For us, for the universe we see, if we lose time we lose anything which might be called existence.

    Also, a semantic issue that bothers me, time travel is indeed possible(your doing it right now) and in fact we can travel into the far future if we can accelerate to relativistic speeds, however time time to the past seems impossible. Why is that? Good question!
  4. Mar 16, 2009 #3
    The problem with a question like this is what do you mean by exists? It is not really sensible to ask if an abstract concept to measure change, implemented by humans exists or not. It is exactly the same as asking if distance or volume exists.
  5. Mar 16, 2009 #4
    Question: Why is it impossible for us to have experiences if time doesn't exist? You state it as a fact but do not answer why time is needed for it. Why if we lose time do we lose existence? Can you explain this? I see it stated as a fact over and over, but with no solid logic behind it.

    Also, I don't think I came across my point clear enough. I believe time is still needed but that we are thinking about it incorrectly. We think of time as a "river" that can be contracted and expanded (slowing and speeding time). However, all this is is slowing down or speeding up change, in relation to another object (as I said before, generally an Atomic Clock).

    If you consider the points I made, I'm not traveling through time right now but just experiencing change, with the amount of change being measured by time, relative to an Atomic Clock. Let's say however that I did somehow travel into the far future, what would be changed? Only me? Everything around me? Would I have done everything that I would have normally done? Probably not. This is because I am not actually traveling into the future, I am only speeding up change.

    This is my point. Distance and volume do not actually exist, they are concepts created by us to measure change. Same with time. Unless I'm understanding wrong, people consider time to be something that is "exists" in the sense that it can be manipulated. E.g. sped up and slowed down, travel into the future and possibly the past.

    Also, quick question: If time (as we think of it now) is dilated by Gravity, etc then that would mean everything, everywhere is at a different point in time(even if it is only a small amount of time). How does that work?

    Actually...second question: What do physicists consider traveling into the future? Would everything change or only the object that is being manipulated? E.g. if I went into space, traveled into the "future" and came back to Earth, would everything on Earth be in the "future" also? E.g. would it have changed at the same rate I did somehow? If it didn't, how can I tell that I actually traveled into the future?
  6. Mar 16, 2009 #5


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    Time is not only a system of measure of change, but the necessary medium in which change can occur, i.e. it is an ordering of events. Similarly, space is the definition of the necessary medium in which events can occur. Therefore, as our perspective of the world is a changing environment of events time and space must necessarily exist.

    This is why it is equally meaningless to say that time and space don't exist as saying distance and volume don't exist. They are concepts which don't have the property of 'existence' similar to what one would call an object 'existing'.

    The quantification of time is not equivalent to the existence of time in itself. We find atomic clocks to be extremely accurate in measuring equal intervals of what we define as time, and it is therefore natural to define the time unit on this. Time in itself is not a consequence of its quantification. That would be like saying that the concept of distance or volume is dependent on objects to measure.
    Last edited: Mar 16, 2009
  7. Mar 16, 2009 #6
  8. Mar 16, 2009 #7


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    Without 'Time', faster and slower makes no sense.

    And the speed is measured as dx/dt, where x is some measure of distance or displacement (spatially) and t is measurement of time, and without acceleration or constant speed, v = Δx/Δt, where Δx = x2-x1 and Δt = t2-t1.
  9. Mar 16, 2009 #8
    My question is: Why is time a necessary medium? We need time to measure WHEN the events happened, but we don't need time for the events TO happen.

    Exactly, from our perspective time and space must exist to measure change. However from an independent standpoint, do we really need time?

    I wasn't saying this. I was saying that currently we don't consider time as the same concept as distance, volume, temperature, etc. I didn't say distance, etc didn't exist, I was saying that we need to consider time as a concept similar to these.

    As I said before, lets say we move that atomic clock near a binary star, does our time still hold true? No, because it is relative. Just because we as humans can live by this generally accurate time does not mean that it will hold true for the physics equations that are being written. Also, I was not saying time as a concept is exactly the same as distance/volume but holds many similarities. Similarities such as it doesn't exist until someone measures it(using a ruler, or maybe an atomic clock?).

    I'm not disputing this. I believe we need time to measure "faster" and "slower" but that it is relative. All I'm saying is we don't need time to "exist" for events to happen.

    My overall point: I believe we need time to measure change but that time isn't needed for events to happen. Does anyone have any counterpoints to this?

    Also, thank you everyone for all your reply's. It's helping me get a bigger picture of time and how it's used.
  10. Mar 16, 2009 #9
    Also, I've probably contradicted myself somewhere since I didn't have a clear view of what I was trying to explain but all the counterpoints are helping my grasp that clear view now. Thanks for all the replies.
  11. Mar 16, 2009 #10

    Actually I should take this back. Distance exists if it isn't measured, I guess the only similarity is that it is measuring something relative to something else. E.g. we measure distance by using the meter standard http://en.wikipedia.org/wiki/Metre the same way we measure time using an atomic clock.
  12. Mar 16, 2009 #11


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    This is not about what why and how we use the concept of time, but whether it is a concept that should be considered as 'existing' or 'non-existing' in the same way as an object. In our perspective we observe events in an ordered sequence. As a part of the definition of time it is what allows us to experience events in an ordered sequence. The whole idea of change or order of events is related to the concept of time. Without time, we have no concept of change.

    Compare it to the statement that "distance doesn't exist". Without distance, we have no concept of length. I.e. it would be meaningless to talk about length and still say that distance doesn't exist.

    It isn't impossible to define a world without the concept of time. It would, however, not be what we percieve as our universe.

    Well, you did say

    As previously mentioned, the concept of "fast" and "slow" lies within the concept of time.
    Last edited: Mar 16, 2009
  13. Mar 16, 2009 #12


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    Actually, one meter is defined as the length light travels in one second divided by 299,792,458
  14. Mar 16, 2009 #13
    Our universe is evolving. Presumably, everything in our Universe is in motion. Time is an index of change or motion. If no time, then no motion. If no motion, then no Universe. If no Universe, then no existence.

    That might be the common view. It's probably a byproduct of our internal indexing of our sensory data, and a general lack of rigor wrt defining the meanings of the words we use.

    What we're actually doing is associating accumulations of periodic oscillators with intervals of change or motion (incongruent spatial configurations). This is how we generate time indexes.

    We're, apparently, part(s) of an evolving Universe. We chart or index this evolution using clocks (internal and external). These indexes are what we call 'time'.

    Afaik, the only way you could travel into the distant future would be to move veerrry faaast for a while. You can do the standard SR math. If you took a trip to the nearest galaxy and back, travelling at an average speed of, say, c/2, then even though you will have counted the same number of Earth-Sun years during your trip as the people who stayed on Earth, you will have aged much less than them.

    Apparently, the periods of oscillators are lengthened by acceleration. The physical reason for this is unknown, afaik.

    I agree that they're concepts. But, concepts exist don't they? The time indexes that we internally and externally construct do exist, I think.

    I agree that this is a popular misconception of what time is.

    I think maybe this is just a semantic problem. You can adopt a holistic view of our Universe where this isn't a problem.

    Well, if it didn't, then you probably didn't travel into the future. Anyway, afaik, as I said above, the only way you can travel into the distant future is by moving around real fast and aging at a slower than normal rate.
  15. Mar 16, 2009 #14


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    Time is a very tricky topic, and many philosophers and scientist has debated time for years.

    I would define it like this: Observed time is a measurement of change within a margin of error.

    Take two atomic clocks and set them equally in time. Put them in two different airplanes that are perfectly side by side on an extended runway. One airplane will travel east until it goes completely around the world and lands back on the runway. The other airplane will go west until it goes around the world and lands back on the same runway. Both airplanes never need to land, fly the exact same distance, and land at the same time. Both airplanes have equal acceleration and speed.

    Will the two clocks be equal in time?

    Time cannot be standardized because it is relative to the observer.

    First lets define time travel: "To go from present to a future date in such a fashion that a gap is created in the time-line where you do not exist."

    I believe that is completely impossible.

    I don't think time is require for existence, but I believe it is require to perceive it.
  16. Mar 16, 2009 #15
    I don't understand why we need time in order to observe events in an ordered sequence. If we didn't have time in the way we think of it now, how would the events be observed? Would they somehow be different? Would they not occur in the order they do now? I understand we need time to help us as humans understand and measure the differences between "two points in time" but this is strictly for our use. Is the universe somehow aware that there was a past?

    Yea, I was completely wrong on this one. It made sense when I first thought about it but then I thought again...then again...and I still failed :P

    I don't understand, why/how would our perception change?

    This was one of those times, I fail :(

    I'm not debating this, we created the concept of time to measure the "fastness" and "slowness" of things, but time isn't needed for these "things" to exist is what I'm saying.

    This interests me. Time is an index of change or motion? I'm probably wrong but does this somehow mean that the past is being recorded? How is this possible?


    This is going beyond me. What information does this time index hold?

    This raises a lot of questions for me...
    To make it simple let's say the traveler traveled for 10 Earth-Sun years but only aged 5. How did he count 10 years in only 5 years of aging? Would he notice he wasn't aging as fast? Would it feel like 10 years passed by to him? Where are the 5 missing years that he didn't age? If he aged twice as slow, in the same amount of time, how does the slowing of time explain how he counted 10 years? It seems to me that, the faster you go, the longer the oscillations take, the longer it takes for the change to occur. This wouldn't really be slowing down time, but slowing down change...?

    I don't know. It might be the way I think of the word, generally when I use it I think of an abstract idea that doesn't actually exist but is useful in describing something, but I don't think that's the definition for concept. I'll see if I can find a better word :P

    Isn't this partially what you are saying? Moving faster/slower speeds time up/down?

    How does it not become a problem? Wouldn't it be a bigger problem since the Big Bang is the most accepted starting point for the Universe? If time comes to an almost complete stop in a large gravitational pull how does anything happen?

    Once again thanks for taking the time to post replies! This is making me think a lot more.
  17. Mar 16, 2009 #16


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    This is exactly it. Time is the concept of the ordered sequences of events which, in any form you may suppose, is necessary for us to experience them. An eventless world would not be a world in which we could percieve anything. Hence time is the necessary medium for us being capable of this. The theory of relativity tells us, though, that the order of these sequences of events is not at all constant in other frames of referances.
  18. Mar 16, 2009 #17
    Probably not, but not in any perceivable amount.

    Yes I understand. There are lots of things relative to us however, we have Earth's Gravity, the Moon's the Sun's, etc but that does not stop us from using mathematics and logic to derive "standards" that seem to fit.


    Why is time required to perceive existence?
  19. Mar 16, 2009 #18

    Aren't the ordered sequences of events going to happen even if we don't measure them (with time)? Would they somehow not happen?
  20. Mar 16, 2009 #19


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    They wouldn't because of the rotation of the earth.

    I think you misunderstand the idea of relativity. It does not mean relative to us as a group, but relative to each person. So two people could experience the same change but perceive different times. For example, take that clock example. If you had a 3rd clock sitting on the runway, it would be different from the others. To that observer, it would look like the planes took off and landed in the same amount of time. However, when you compare clocks, all of them are different.

    Because thought, perception, and all other senses require time. If you think of something new, then a change occurred. No time, no change.
  21. Mar 16, 2009 #20


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    Think of time as a movie. no time = pause. With Time = play.

    well it is an abstraction. You don't have to have a ruler to measure distance.

    Time is like a number line that always goes forward. <-0-1-2-3-4-5-6-> (secs)
    Between each number, an infinite amount of changes occur. We cannot measure time with that kind of accuracy, but take sort of a guess on the margin of error or ignore it entirely.

    The past is being recorded by your brain. I'm guessing that everything would become perceived as very random without that ability.

    He would have counted 5 years, but the people on earth would have said 10 years. No he wouldn't notice he wasn't aging as fast. We have had changes in our time due to orbits, but you didn't notice that change did you? =0)

    Think of it as slowing everything down when you get faster. His thinking process takes longer, his aging takes longer, everything takes longer; however, he will not notice that change.

    That is exactly what happens, change slows down as you go faster.

    Things can be outside of a strong gravitational pull. We are outside of black holes yes?
    Last edited: Mar 16, 2009
  22. Mar 16, 2009 #21
    I think this is an overused, oversimplified explanation for relativity. To the observer and the people in the planes, they took off and landed in the same amount of time. Just because the clocks are off does not mean that somehow "time" was changed for them. Think about how time is being measured. Why couldn't it be that change was occurring slower or faster due to external forces, making the clocks slower/faster?

    I don't quite get the logic in this. Basically if we didn't exist, time wouldn't exist? I understand that we as humans need time as a concept to get by in day to day life but does that mean that time exists beyond our thoughts? Only we as cognitive beings need to think of time...everything else just changes.
  23. Mar 16, 2009 #22


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    But time was changed for them and that is the important lesson here.

    Forces cause time dilation.

    The process that time measures does exist. The clock on your wall, is an abstraction to measure that process.
  24. Mar 16, 2009 #23
    This doesn't really explain anything. The Universe isn't even close to a movie :D Plus you can rewind movies.


    This only specific to cognitive beings though.

    So he didn't actually travel into the future, the speed he was going at just slowed down any change. If I froze myself and unfroze myself 5 years later, I wouldn't say I traveled in time because everyone else was 5 years older.

    What about the Big Bang? When everything was in a sort-of black hole. How did anything get out if time was basically frozen and change couldn't occur?
  25. Mar 16, 2009 #24
    How was time changed? When you say "time was changed" what you really mean is that their rate of change was slowed/sped up. If one plane had its rate of changed slowed, and one had it increased that wouldn't necessarily mean "time" has changed. It can mean that they aged faster/slower relative to the observer on the ground. Do you see the point I'm making?
  26. Mar 16, 2009 #25
    ******** philosophical musing doesn't make something deep.

    Time exists in a sense different from just being space because if it wasn't different, then Lorenzian manifolds wouldn't need to be Lorenzian but would just be Riemannian.

    The definition of time is very specific to the observer, but there is still a required notion of time in most cosmological models.
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