On the Impossibility of Time Travel by J. C. N. Smith

J. C. N. Smith

Mr. Johnstone,

Thank you for directing my attention back to Peter Lynd's discussion thread, and also for putting in a good word there for some of the ideas we've discussed here. As you'll no doubt see, I added my two cents worth to the stew that was brewing there.

I somehow can't help wondering whether our way of thinking about time may just be too simple for many people to grasp. In discussing our ideas, people use terminology such as "the configuration of the universe *at* a particular time" (my added emphasis), but they don't seem to grasp the (perhaps too subtle?) notion that the the configuration of the universe *is* the particular time. The particular time and the particular configuration of the universe are one and the same; they're inseparable.

I've finally completed my reading of all 114 essays, and probably will now go back to re-read a good many and vote on rankings. I was reluctant to make judgements about relative rankings without first having gotten at least a general feeling for the whole spectrum. Overall, I'm well impressed by their quality. Tough competition! In this regard, I can't help wondering whether you may have given any thought to the idea of possibly submitting an essay yourself? You certainly seem well qualified to do so should the spirit move you.

Cheers

J. C. N. Smith

Mr. Silin,

Thank you for your follow-up comments which clarify the points I had asked about. That is helpful. For the moment, I have no other questions. I've been kept very busy reading all the many interesting essays which have been submitted, and now probably re-reading many.

Thank you again for your reply.

Cheers

J. C. N. Smith

One addendum for the record: I just noticed today that my on-line essay 'Time: Illusion and Reality,' which is reference 4 to my current FQXi essay, has recently been dealt a grievous blow in terms of its on-line appearance. Google, in its infinite wisdom, and without notifying me of its plans, did a "migration" of the essay (I'm more inclined to think of it as a death march) from its former home as a Google Page to its current home as a Google Site. In the process, the formatting and overall appearance were badly mangled, making it aesthetically most unpleasing. In fact it reminds me of one of the classic movie-style ransom notes consisting of words clipped from a newspaper and pasted together for the note.

I'm consulting with the Google Help forum seeking ways to rectify the situation, but in the meantime I'm ashamed to refer readers to view the site. The words themselves remain intact should anyone who wishes to read it in the interim be brave enough to stomach the site's overall horrid appearance. Sorry!

[deleted]

To J. C. N. Smith:

While I largely agree with your position, I would like to question your ubiquitously shared opinion that predictive power is the only criterion for a theory. I rather consider science a puzzle whose element do or at least will fit together with no contradiction and no arbitrariness.

To Alexander Silin:

I cannot see any action at distance on physics of plasma.

Regards,

Eckard

[deleted]

I meant "in" physics of plasma. Sorry for my typo.

[deleted]

Mr Smith,

In relation to people (mis)interpreting your configuration being *at* a particular time rather than *as* a particular time, I am thinking that it may be as simple as a matter of grammar! The fact that we talk in singular terms, ie "time" and "configuration", may also connote a singular "entity"(now?) and a singular separate entity "configuration? Of course what we are really describing (without wanting to second guess you!) is an evolving *continuum* with no inherent "now" or, therefore, "future" or past".

It is interesting that Peter Lynds thought I, (and Terry Padden), were assuming that simultaneity implied the presence of "nows" and that your main principle implied the existence of an instant. Peter comes from the standpoint of a tenseless, non-discrete(except for mass/energy) reality, where time (and space?) don't exist, so that a "singular" description may be interpreted as an instant or quantum of time. Apart from the fact that I (we) think that time doesn't exist a priori, if it did, and if it was a *real* variable, then I would agree with him that quantum time would preclude motion or any state evolution because there are no "temporal interactions" to mediate change/evolution.

With the evolving configurations *as* time model, we are trying I think to re-interpret the notion of co-ordinate time in GR. So that the 4th co-ordinate and hence simultaneity, is described in terms of observer dependant positions in relative configuration/velocity space.

BTW, I support Eckard's query:-

"I cannot see any action at distance on physics of plasma."

I would say that action at a distance is more evident in, say, the formation of a complex crystal!

Cheers

Roy

[deleted]

Sorry for this quick follow up, but I just had a thought rergarding the lack of "tense" or external time in objective reality, ie past, present, future. If we look at the notion of future, and think of the deadline of this essay contest for instance, all entrants were told the closing date was October 2nd, 2009. What is this really saying? It is combining a clock and calendar reading calibrated by known physical cyclic processes to describe a *particular* combined configuration of Earth's rotation angle and orbital position. Therefore if we dispose of all our clocks and calendars, we could still, with some effort, keep track of these processes and know to a good approximation when the deadline has arrived. However, if some natural catastrophe beset the solar system, completely changing Earth's rotational velocity and/or axial orientation and/or orbital motion, no one would have any way of knowing when the deadline had arrived!

Of any use?

Cheers

J. C. N. Smith

Mr. Johnstone,

You wrote, "Of course what we are really describing (without wanting to second guess you!) is an evolving *continuum* with no inherent 'now' or, therefore, 'future' or 'past'."

My view is that "now" is the configuration of the universe which we observe when we look around us. This configuration is constantly evolving. The "past" is all of the configurations which preceded the one we observe with our senses. These previous configurations are no longer objectively real, but they once were objectively real. The "future" is all the configurations which will follow the one we observe with our senses. These hypothesized future configurations also are not objectively real "now," and unlike "past" configurations, they never have been objectively real. Moreover, except as intrinsically imperfect extrapolations from the configuration which we observe by looking around us, these future configurations are unknowable.

In discussing this way of looking at time as configurations of the universe it is important to remember the analogy of the elephant and the blind observers, each of whom has access to only a relatively small portion of the elephant. Their descriptions of the elephant may vary only slightly or dramatically, depending on how closely they are positioned to one another while carrying out their observations. The fact that their descriptions may vary dramatically or hardly at all, however, should not be taken as evidence that the elephant is not real or that it does not have a real configuration or that the various observers' descriptions of the elephant are not all equally valid. The universe is our elephant. Each of us sees if from a different vantage point. This is essentially the "one universe as seen by many observers rather than the many universes as seen by one mythical observer outside the universe" as advocated by Lee Smolin in 'Three Roads to Quantum Gravity (p. 48).

I agree with your comments relating all this to the contest deadline. Clocks and calendars are useful *only* insofar as they serve as a convenient shorthand for accurately referring to larger, more or less predictable, evolving configurations of the universe. I discuss this in some detail in my essay 'Time: Illusion and Reality' (to which I'm currently embarrassed to refer readers due to its horrible superficial appearance, as described in a previous post). I hope this is helpful.

Cheers

J. C. N. Smith

Mr. Blumschein,

You wrote, "While I largely agree with your position, I would like to question your ubiquitously shared opinion that predictive power is the only criterion for a theory. I rather consider science a puzzle whose element do or at least will fit together with no contradiction and no arbitrariness."

I totally agree with you, and, in fact, in an earlier post I mentioned what I believe is another important test of the value of a theory, which is its explanatory power. A good theory should help us explain and understand our observations about our universe in ways which are, to borrow words from Mr. Terry Padden's essay, rational and reasonable.

Cheers

J. C. N. Smith

Hallelujah! The errant website with my other essay, 'Time: Illusion and Reality,' has been put back into reasonably presentable shape, at least from the standpoint of superficial aesthetics. For better or for worse, the thoughts to be found therein remain unchanged. I still stand by them. Anyone who wishes to read it may find it here.

jcns

[deleted]

Hello Mr Smith

Just a "heads up". If you are not already aware, Lee Smolin is working on a new book "The Reality Of Time"! Not sure what the ETA for publication is yet though.

Cheers

J. C. N. Smith

That's fantastic news! No, I had not heard about it. I just hope Mr. Smolin has been reading all of our essays and threads so he'll have the benefit of our collective "wisdom," such as it is. Between the new Barbour and Smolin books we should have a field day sorting out all the new thinking. I know the two of them have collaborated in the past. It would be nice if their two books could somehow be complementary. Maybe asking too much? Regardless, thanks for the heads up. And if you learn any more details I'll be all eyes and ears.

Cheers

J. C. N. Smith

Mr. Johnstone,

It should go without saying that I was speaking somewhat with tongue in cheek when I said in my previous post that I hope Mr. Smolin (and by extension, of course, Mr. Barbour and others) will not overlook the collective "wisdom" to be found among these FQXi essays and threads in the course of writing their new books dealing with the nature of time.

But my comment was not totally without a deep note of seriousness as well. It will be a huge disappointment to me if we continue to see books written on the nature of time by prominent, well respected physicists which do not, at a bare minimum, *discuss* the concept of time which we've been advocating here. Certainly, to some extent, Barbour's 'The End of Time' touched on our ideas, but only in a somehow frustratingly tangential way involving the disavowal of motion, a notion with which we both strongly disagree. Even if their new books were to reveal some deep, logical flaw in our concept of time it would not be totally demoralizing, so long as they could explain in a clear, rational, reasonable fashion (to again borrow Mr. Padden's words), why this way of thinking about time is not useful and/or productive. As the saying goes, time will tell.

Cheers

[deleted]

Dear Roy Johnstone,

If I recall correctly, when Einstein spoke of spooky action at distance he referred to claimed propagation with superluminal velocity. In my essay I mentioned Nimtz.

Regards,

Eckard

[deleted]

Dear J. C. N. Smith,

Since you dealt with the impossibility of time travel you can certainly tell me who was the first one to suggest such nonsensical possibility. I am aware of the religious belief of repetitious birth. However, as a bloody layman, I suspect that a cheeky physicist looked at the putative symmetry of laws of nature and concluded from the mathematical possibility that time travel is physically possible, too.

Who was it? Who was the first one to ascribe reality to the complete Schwartzschild solution in excess of plus infinity and minus infinity? If I recall correctly, it was not S. himself. Who was the father of such overly speculative physics? Did nobody object?

When I read Feynman's Nobel lecture, I was deeply disappointed because he revealed his utterly speculative approach instead of restriction to checkable reasoning.

Curious,

Eckard

J. C. N. Smith

Mr. Blumschein,

Your question is a good one! By way of offering a simple reply please allow me to refer you to the Wikipedia write-up on time travel, which actually is quite informative as to the history of the concept, etc., and which may be found here.

The allure of the idea of time travel is certainly understandable. Who wouldn't be tempted to travel in time if it were possible? Given this natural allure of the concept, in combination with our species' penchant to indulge in wishful thinking, and voila! It's the stuff of some pleasant fantasies.

Cheers

J. C. N. Smith

Mr. Johnstone,

I don't know whether you've been following the FQXi blog on the shutdown of the LHC, (to be found here). I just very belatedly read through it for the first time today and added my two cents worth to the bottom of the discussion. We really need to get on with moving this sort of talk about time travel into the same category as talk about alchemy and astrology where it belongs, once and for all.

Cheers

[deleted]

Dear J. C. N. Smith,

If there was indeed something like an a priori given spacetime, then I would agree that it could be reasonable to ponder over looped worldlines. So the first father of timetravel in physics might be Einstein's teacher of mathematics Minkowski. Perhaps it was he who degraded the science of physics to science fiction including the perhaps failing search for SUSY. I am not sure but maybe you too are supporting the alternative mentioned by Zeh when he distinguished between direction of time and Minkowski's direction in time on p. 1 of introduction. Let's vote for realism, i.e., d. of t, not d. in t. .

Seriously,

Eckard

I do not amiss of you are calling me Mr.

Frank DiMeglio

Hi J.C.N. Smith:

The essay that wins this contest should explain/advance the understanding with respect to sensory experience (including gravity and electromagnetism) IN GENERAL.

I will now prove that how space manifests as electromagnetic/gravitational energy is THE central and MOST valuable physical idea.

The reduction in the range and extensiveness of feeling (of the body) while dreaming/sleeping is very relevant. The completion and balancing that dreams/sleep give to the unification of gravity and electromagnetism/light is consistent with the 90 degree angle of the two experiences/states (waking and dreaming). (Gravity is fairly constant at/near the surface of the Earth.)

The extremes of distance/scale and speed point up the connection involving electromagnetic/gravitational space (e.g., the Sun and photons).

The dream combines (and includes) invisible and visible space in conjunction with exhibiting wave/particle duality.

The unification of gravity and electromagnetism/light occupies the center (and best) position with regard to improving our understanding of physics in general.

To unify gravity and electromagnetism/light fundamentally and comprehensively, balancing/unifying scale by demonstrating gravity as repulsive and attractive AS electromagnetic energy/light is required. It is critical to demonstrate electromagnetic energy/light as gravitational space. The unification/balancing/inclusion of both invisible and visible space is central to:

1) Balancing/unifying scale and...

2) Balancing attraction and repulsion in conjunction with space manifesting both gravititationally and electromagnetically. Think wave/particle. Note that the repulsive and attractive aspect is manifest in the variable distances of space/distance in the dream (think of this in relation to touch and feeling as well).

These ideas need to be applied to atomic structure/interactions, and to electromagnetism/light and gravity generally. How space manifests as electromagnetic/gravitational energy is a central and very valuable physical idea. Do you see how this post (and my essay) cover/include: space, time, matter, energy, wave/particle, balancing/varying scale, repulsive/attractive, and visible/invisible?

You can see how the aspect of cylindrical space also applies to/is manifest in dream experience. Schroedinger was perplexed enough by life to suggest a new type of physical law. This new physical law is the known mathematical union of Einstein's theory of gravity and Maxwell's theory of light in a fourth spatial dimension. It is common sense (and obvious) that this unification must be (and is) present in our experience. The physical reality of said unification is dream experience. I have proven this definitively (in detail and with specifics). Note that I have demonstrated how time and space are both balanced in a fourth dimension. (I am not so concerned with what is the Kaluza-Klein interpretation of the unification as I am with the unification itself.) Dreams make thought more like sensory experience in general (including gravity and electromagnetism/light).

Reductionist thinkers tend to pick apart my essay, as they lack [what is a greater] integrated extensiveness in their thinking/knowledge.

The increased transparency/invisibility of space in astronomical/telescopic observations is very important/relevant as well. What are your thoughts on all of this please?

My essay (fourth from the top) is very important on the issue of time.

I would appreciate your comments and rating please. Please read the posts under the essay as well. Thanks. Frank

J. C. N. Smith

Mr. DiMeglio,

You wrote, "The reduction in the range and extensiveness of feeling (of the body) while dreaming/sleeping is very relevant. The completion and balancing that dreams/sleep give to the unification of gravity and electromagnetism/light is consistent with the 90 degree angle of the two experiences/states (waking and dreaming)."

This quotation captures the gist of my problem with your essay, which boils down to its heavy focus and reliance on dreams and/or sleep, neither of which currently is sufficiently well understood to serve as a credible basis for a theory of physics. This is not to rule out the possibility, of course, that this situation might not change at some future time. Sorry, but that's my take on it. Good luck though.

Cheers

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