Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

A Thought Experiment

  1. Apr 25, 2004 #1
    Well guys, I'm back. I thought about it some more and perhaps I have a way to reach you in spite of your utter refusal to think things out.

    In case anyone reading this does not know who I am, I am that idiot who has suggested that the physics community has over looked something significant. I fully realize that something like that could not possibly be true so don't bother trying to tell me how ignorant I am.

    I am the person who claims that "clocks measure time" is an erroneous statement! In defense of that position, I suggest the following thought experiment involving any conceivable "ideal" clock:

    The experimenter will throw the clock across the room where upon it is smashed to smithereens.

    Now, let us examine that experiment from a number of different frames of reference. I make the claim that all observers (totally independent of their frame of reference) will find the reading on that clock at the moment it leaves the experimenters hand will have a specific value. They will all agree as to what that reading was and the reading has absolutely nothing to do with their frame of reference.

    I further make the claim that all observers will find the reading on that clock at the moment it is smashed to smithereens will also have a specific value. And once again, they will all agree as to what that reading was. Once again, that reading has absolutely nothing to do with their frame of reference.

    In fact, they will all observe that clock to be a measuring device which starts with some reading and terminates with a second reading, having progressed through all the intermediate readings between the two. The only differences they will claim have to do with the coordinates describing the event in their personal frames of reference. In particular, the length of time required for the event to occur will vary from frame to frame. What is important here is that the reading on the clock has absolutely nothing to do with the "time" used in the description of the experiment in anyone's frame of reference!

    That fact must be true as the functioning of the clock is determined by physical laws and those physical laws are (from the axioms of relativity itself) independent of your frame of reference! The functioning of that "ideal" clock cannot possibly be a function of your frame of reference!

    Now, what I have given is a rather extreme; however, it is an accurate description of the functioning of an ideal clock. Any "ideal" clock proceeds from significant moment to significant moment and, if we are to accurately assess the behavior of that "ideal" clock, we must take into account each and every interaction event between that clock and the rest of the universe. In the "ideal" case, all events are significant!

    It is not necessary that the "significant" interactions destroy the clock. That example was created to get your attention to the specific behavior of an "ideal" clock. Just as the thrown clock in the experiment did not measure time in anyone's frame of reference, no "ideal" clock in the universe can possibly measure time in anyone's frame of reference.

    On the other hand, the clock certainly has a very specific periodic behavior which we find very convenient in all measuring devices. So it certainly can be thought of as measuring something. If it isn't "time" which is being measured, exactly what is being measured?

    If any of you geniuses out there can wrap your head around that, I look forward to your responses.

    Have fun -- Dick
  2. jcsd
  3. Apr 25, 2004 #2
    Clocks don't measure time, they measure seconds. Seconds are actually an on going rythm. Time is a dimension.
  4. Apr 25, 2004 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If clocks don't measure time, then what does?
  5. Apr 25, 2004 #4
    I'm no genius, but I would make an observation, if you will. Science has more unknowns than knowns. That is part of why we are so fascinated by it, because any one of us can be the first to discover it. Discovering it, of course, meaning that it was always there, but we have just identified and/or defined it. In the meantime, I would remind you that most of the greatest scientist did not conform to all the ideas that the scientific community adhered to, and as a result were often challenged and ridiculed. In the end, however, they were the last to laugh. So keep 'em coming!
  6. Apr 25, 2004 #5
    Time and "seconds"!

    I will excuse you as, from your public profile, you are but 12 years old which by my estimates would put you in the fifth grade or there abouts. I am sorry but, in order to understand my post, you need considerably more education than you most probably have.

    "Time" is a thing physicists think they can measure. Seconds are a unit of measure in that "thing"; just as feet are units of measure of length. That is to say, time is to seconds as length is to feet.

    My complaint is very simple: though time is a very valuable concept, clocks do not measure it.
  7. Apr 25, 2004 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If clocks don't measure time, then what does?
  8. Apr 25, 2004 #7
    You tell me!

    Time is a very useful concept used in physics. My argument with physicists (and, by the way, I have a Ph.D. in theoretical physics) is that they are very confused by the ancient (pre-Einstein) idea that clocks measure time. In fact, it is my position that Einstein himself was confused by the idea (a careful analysis of Einstein's work reveals, to any thinking person, that he proved clocks do not measure time).

    My position is very simple, though "time" is a very useful concept, it is not a measurable variable and physicist make a major error by assuming it is! Can you understand my complaint?

    Have fun -- Dick
  9. Apr 25, 2004 #8


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    All right, so you assert time is immeasurable.

    Before I touch on that, let's ask the next logical question, "What do clocks measure?"
  10. Apr 25, 2004 #9
    Apparently neither am I! When I was a graduate student, I asked my advisor a question which concerned me. His answer was quite concise: he said, "Only geniuses ask questions like that and, believe me, you are no genius!"
    Now here you are a man after my own heart. I have always held as self evident the fact that, if you can't define what you are talking about, you don't understand what you are talking about.
    Well, if ridicule is an indicator of a "great scientist" then I certainly have that base covered. I have been ridiculed for more than forty years at the latest reckoning. I can show at least a dozen institutions which have utterly refused to even talk to me. And no journal I have made a submission to has even descended to consider publishing my ideas (every rejection I have received says I am submitting to the wrong journal).
    Well, here I agree with you. I am, after forty years, still interested in finding someone who will think about the issue.

    Have fun -- Dick
  11. Apr 25, 2004 #10
    Now I was looking for someone who had the intelligence (or at least the interest) to answer that question themselves; however, since you have directly asked me that question, I will give you the correct answer: clocks measure, exactly, what Einstein referred to as the "invariant interval"! The problem here is that, in order to understand "what clocks measure" you need to have an intimate understanding of relativity. With regard to that issue, I have no idea of the limits of your education.

    Have fun -- Dick
  12. Apr 25, 2004 #11


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I would have said "proper time", but same thing. (I had missed your asking of this question at the end of your original post)

    I was originally planning on going through, step by step, the construction of "coordinate time" in an inertial SR frame of reference, to see if and where you had a problem with it... my presumption is that if you had a problem with the concept of time, and it wasn't in regards to proper time, then it had to be with coordinate time. However, I'll now assume you're familiar with the construction of coordinate time, so I'll ask, do you have a problem with it?
  13. Apr 25, 2004 #12
    Ok so time according to you is not a measurable variable, but seconds are a unit of measure in that "thing" called time….. This all sounds like “you think that time has to be defined by whatever time really is??”

    Yes a 12 year old will struggle with the deep thinking needed to understand the very complex process of lobbing a clock at a wall….. LOL

  14. Apr 25, 2004 #13
    Questions to Doctordick : Do you mean that time has two faces? One relative and the other global ? A contradiction like SR time and QM time?
  15. Apr 25, 2004 #14
    I confess that I may not have sufficient education to fully understand all the concepts here, but this is my take on the matter. First of all, nobody in this thread has put forth a firm definition of time. I think this is the primary source of controversy. As I see it, in the context of this thought experiment, time is only used to show the relative frequency of events (I'm not sure that's a good way to word it, considering frequency is defined using time). For example, between two movements of the second hand on the clock, there will be approximately 2x10^15 oscillations of radiation from a sodium lamp. In other words, the clock is used to give the user points of reference from which to gauge whether two events will coincide. I don't mean this as a contradiction to your ideas, Dick, but how does that differ from measuring time?
  16. Apr 25, 2004 #15
    I thought I made myself clear! My complaint is very simple: physicists are confused! The common perception (presented in almost every presentation of physics concepts) is that "clocks define time". My position is that this is a very erroneous concept. A concept which leads physicists to ideas which are fundamentally undefendable. My position is that clocks measure "proper time" a fundamentally different thing.

    Their failure to take into account the fundamental difference between the two concepts leads to confusion on a level of great significance (in my humble opinion). If you can not see the difficulty, then you are part of the problem, and not part of the solution.

    Have fun -- Dick
  17. Apr 25, 2004 #16
    Ok, if you have such a good view of physics phenomena, you give me your analysis of the thought experiment I proposed. I have no idea of your academic background so I cannot judge where you are coming from at all. I have utterly no idea of what you have in mind.

    Have fun -- Dick
  18. Apr 25, 2004 #17
    I made a very simple statement: "clocks do not measure time". What I am saying is that "time" is a concept which reflects a variable which is not measureable. I am not saying that it is not a useful variable when it comes to physical phenomena; what I am saying is that the variable is not measureable!

    If you cannot understand that, go back and read my thought experiment again; carefully this time!

    Have fun -- Dick
  19. Apr 25, 2004 #18
    Yes, you have put your finger on the essence of the difficulty. As far as I am aware, the common definition of "time" (as used by physicists) is that "time" is what is measured by clocks.

    However, after adopting this definition of time, they proceed to act as if this definition of time is consistent with the common definition of time used through out the ages. My position is that they are overlooking a subtle fact essential to understanding the functioning of the universe. If your position is that their perception of the issue is correct then you are not thinking the issue out.
    Now right here you are confronting the problem without realizing the existence of the problem. The issue of time is, "will the two events coincide"! If your definition includes the fact that events at the same time must coincide, then clocks will not provide that information. It is a well known consequence of relativity that two travelers (meeting after having followed different space-time paths through the universe) will not agree on the "time" if they use their personal clocks as a measure of time.

    Think this out a little bit.
    Please tell me what do you mean by "measureing time".

    Have fun -- Dick
  20. Apr 25, 2004 #19
    A clock is a measure of time, but a peanut butter and jelly sandwiich can measure time also. The point here is that existence is a measure of time.
  21. Apr 25, 2004 #20


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Physicsts spend a great deal of effort trying to explain to people that the relativistic notion of time most certainly does NOT coincide with the pre-relativistic notion of time, so I can't fathom where you got this idea.

    When you responded to my post about "coordinate time", did you mean to suggest there is something wrong with Einstein's method of synchronizing clocks in a reference frame, or is it that you simply not like the term "coordinate time" used to refer to the readings on the clocks?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: A Thought Experiment
  1. Thought Experiment (Replies: 20)

  2. Thought Experiments (Replies: 16)

  3. Thought experiment (Replies: 3)

  4. Thought Experiment (Replies: 9)

  5. Thought Experiment (Replies: 13)