On Wed, Feb 5, 2014 at 2:35 PM, Edgar L. Owen <edgaro...@att.net> wrote:
> Jesse,
>
> Let me ask you this simple question. You agree that there is "a same point
> in spacetime" that both twin meet at and in which their clock times are
> different.
>
> How does your theory, or relativity, account for or predict this same
> point with different clock times starting from when the one twin leaves on
> his journey?
>
> Is there any choice of frames which computes this result in relativity
> theory? If so what?
>
Yes, all of them predict it. In the context of any allowable choice of
coordinate system, if two events occur at exactly the same position and
time coordinates, then that leads to the conclusion that they must have
occured at the "same point in spacetime" in a coordinate-independent sense
(understood either in terms of spacetime geometry or in terms of the
operation definition I mentioned). So if any given frame assigns the same
space and time coordinates to a pair of clock-readings for each twin, like
"twin A turns 30" and "twin B turns 40", that implies these events happened
at the same point in spacetime, and it always works out that other frames
assign this pair of events identical coordinates too.
Jesse
>
> If not then we must assume a separate kind of time in which it is true.
> That is p-time.
>
> I think this question gets to the crux of the disagreement....
>
> Edgar
>
> On Wednesday, February 5, 2014 1:40:41 PM UTC-5, jessem wrote:
>>
>>
>>
>> On Wed, Feb 5, 2014 at 10:53 AM, Edgar L. Owen <edga...@att.net> wrote:
>>
>>> Jesse,
>>>
>>> A couple of points in response:
>>>
>>> 1. Even WITHOUT my present moment, the well established fact of a 4-d
>>> universe does NOT imply block time nor require it. Clock time still flows
>>> just fine in SR and GR.
>>>
>>
>> I would agree that the 4D mathematics of relativity theory doesn't
>> require the ontology of block time, though I don't see any alternative to
>> block time besides some sort of "metaphysically preferred" definition of
>> simultaneity (which wouldn't contradict relativity as long as long as this
>> definition wasn't "preferred" by the measurable laws of physics). I don't
>> know what you mean by "clock time still flows" in SR and GR--it only
>> "flows" in the sense that its value is different at different points along
>> a worldline, the same sense in which we could say that "distance from the
>> end of the wire" flows along a piece of wire (i.e. the value of "distance
>> from the end of the wire" is different at different points along the wire).
>>
>>
>>
>>
>>> No clock time simultaneity of distant (relativistic is a better
>>> descriptor) events does NOT imply time is not flowing at those events. This
>>> is quite clear. It's a fundamental assumption of relativity that time flows.
>>>
>>
>> What mathematical element of relativity corresponds to your notion of
>> "flow"?
>>
>>
>>>
>>> In fact relativity itself conclusively falsifies block time as it
>>> requires everything to be at one and only one point in clock time due to
>>> the fact that everything always travels at the speed of light through
>>> spacetime. I find it baffling that so many can't grasp this simple fact.
>>>
>>
>> Huh? "Everything moves at the speed of light through spacetime" is not
>> how most physicists would describe relativity, and those few who do are
>> just speaking in a colorful way about the magnitude of the 4-velocity
>> always being equal to c. And the 4-velocity is just defined as a vector
>> whose components give you the rate of change of the spacetime coordinates
>> t,x,y,z relative to proper time.
>>
>> Nothing about this notion is contrary to the notion of block time--as an
>> analogy, if we have a piece of wire embedded in a block of ice and forming
>> some type of curved shape, and we use an x,y,z coordinate system to
>> describe different points within the block and on the wire, then at every
>> point along the wire we can define a vector whose components give the rate
>> of change of x, y, z coordinates relative to "proper length" at each point
>> (where "proper length" refers to the distance between that point and the
>> end of the wire--or some point along the wire marked "0"--as measured along
>> the the wire itself). And in fact it's not hard to show (I can give you the
>> derivation if you like) that using these purely spatial definitions, the
>> magnitude of *this* vector must always be 1 at every point on the wire,
>> regardless of the shape of the wire. Would you describe this situation by
>> saying "every wire-point moves at the same speed through the block of ice",
>> even though we are talking about wires that from our point of view are
>> completely static, frozen in a particular shape within the block?
>>
>>
>>
>>
>>>
>>>
>>> 2. You complain about me not answering a few of your questions. As I've
>>> explained before I have limited time to post here because running my
>>> business keeps me very busy.
>>>
>>> And please note that a lot of my posts have received NO answers at all
>>> either, e.g.
>>>
>>> a. Several major posts, some as new topics, on my theory of how
>>> spacetime emerges from quantum events. Apparently this has just sailed over
>>> everyone's heads with not a single meaningful comment, not even any
>>> negative ones which is pretty surprising among this crowd! Apparently no
>>> one is interested in understanding the nature of time at the quantum level?
>>>
>>> b. My post on a solution to Newton's Bucket. Also no relevant responses.
>>>
>>> c. Several thought experiments lending very strong support to my present
>>> moment theory, posted just a couple days ago. Again zero response. And
>>> weren't those directed to YOU?
>>>
>>> d. Several thought experiments designed to dig into the fine points of
>>> various aspects of time dilation. Again only a vague comment or two on
>>> 'asymmetry' but zero actual analysis of the points I raised.
>>>
>>> e. Several other new topics on basic issues of science and epistemology.
>>> Again no relevant responses.
>>>
>>
>> Those posts were not part of an ongoing discussion with *me*, though. I'm
>> not asking you to respond to every argument I make, just to respond to
>> posts that are part of ongoing discussions with you, in which I raise
>> serious difficulties with arguments you have presented to me. And I don't
>> mind if you take your time in getting back to me, but it is rather
>> suspicious when you continually ignore my requests to address specific
>> issues I've raised with you, even when you do apparently have time to
>> respond to other posts of mine.
>>
>>
>>
>>>
>>> As for your comment that "you have no idea what moving in clock time
>>> could mean" pull your head out of your physics books and watch your watch
>>> for a little while and see if the hands are moving. If not, you are in
>>> block time.
>>>
>>
>>
>> So does your argument for "movement in clock time" depend on our
>> conscious perceptions, rather than any sort of well-defined quantitative
>> measurements? It's not obvious to me that my perception of movement is
>> anything more than a mental comparison between what I'm seeing now and my
>> very short-term memory of what I was seeing half a second or less
>> earlier...and of course the idea of comparing memories or other records
>> with current observations still makes perfect sense in a block time view.
>>
>> I am interested in the issue of the difference between conscious
>> perceptions ("qualia" as philosophers refer to them) and objective physical
>> facts, and I have considered the possibility that if there is a "theory of
>> consciousness" of the type that the philosopher David Chalmers discusses,
>> then perhaps the "flow of time" would play a more fundamental role there
>> than it does in physics. But I don't see that this implies any *unique*
>> subjective present--if I can imagine a multiverse where different versions
>> of me are having different experiences, I can equally well imagine that
>> there are different mes-at-different-ages having distinct experiences, each
>> of them experiencing their own "flow" of time...it'd be a bit like a series
>> of TV screens which are each playing the same movie, but where each screen
>> is one frame ahead of the screen to its left, so screens at sufficiently
>> far-apart positions can be showing completely different parts of the movie.
>>
>> Jesse
>>
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