Q&A with Paul Davies: What is Time?

John M,

Does the future really go to space? My dictionary tells me that the future is understood as "the period of time that comes after" the current moment. In other words, the position of the current moment on the abstract time scale divides this line into a growing backward arrow of past and a shrinking arrow of future.

Therefore the notions past are never independent from that moment. The future can only become the past if we change its meaning by attributing it to an event.

According to pre-Einsteinian understanding, there is only one common current moment for all locations in the universe and no paradox-free alternative to this reasonably postulated and confirmed in all experience so far ubiquitous synchrony.

You imagine time as something like a signal that propagates. Don't you take a subjectively biased position as did Einstein's use of Poincaré synchronization?

Eckard

"Therefore the notions past are" should read "Therefore the notions past and future are"

Hi Eckard,

e.g. Re your use of the term "Temporal distance".

you seem to be missing my point. For any scientific discussion about some "thing", or "phenomena", to be valid, ( e.g. a thing called "time"), one needs to establish that the phenomena can reasonable be said to exist.

I like posting on FQXI, because it calls itself the Foundational Questions Institute, ( the X symbol stands in for "Physics and Cosmology," our focus).

So this is a valid place to ask foundational questions, i.e. questions about the very roots of our assumptions and theories, and not a place where it ok to just avoid foundational questions, and act as if their answers just exist elsewhere.

( anyone avoiding questions about the foundations of theories etc, here is missing the entire "foundational" point of the institute).

Re this, you start your post above with the word "Temporal",

As in "Temporal distance".

I think it is extremely risky in science if we just casually use terms , e.g. "temporal", as if they certainly relate to existing phenomena, while in fact we are unable to provide proof that the term is valid if asked.

The word "Temporal" implies that you think the concept of "time" is in some way not just a useful idea, but in some way a genuine phenomena.

Therefore, would you please explain...

Q- precisely what your foundational reason is to believe that there is an invisible intangible thing called time, that exists, or "spans" or "passes" etc, such that your use of the term, and thoughts about ,"Temporal distance" is justified.

Many thanks

m.marsden

FQXI video contest entry(s)

Time Travel,Timeless Answers to Prof Brian Cox's Science of Dr WHO

http://fqxi.org/community/forum/topic/2243

Answers to Prof Brian Cox's Science of Dr WHO

Does Time exist? How 'Time travel Paradoxes' can't happen without "the past".

http://fqxi.org/community/forum/topic/2245

'Time travel Paradoxes' can't happen without "the past".

Time travel, Worm hole, billiard ball' paradox, Timelessly. (re Paul Davies- New scientist article)

http://fqxi.org/community/forum/topic/2244

billiard ball' paradox, Timelessly

(auth "A Brief History of Timelessness" > http://www.amazon.co.uk/dp/B00I09XHMQ )

I agree on that FQXi invited and hopefully will go on inviting new questions that may shutter tacit basic assumptions of science. Questioning the existence of time is certainly not new. Most winners of the first contest demonstrated their academic proficiency by efforts to defend space-time and denying some time notions of common sense.

If you ask whether or not something exists you mean is it something real, something actual. Mathematics shows that this is often a tricky and rather futile question. Does the square root of a negative number exist? Obviously not, unless one allows for imaginary numbers.

I feel ignored because I consider the usual, so called scientific notion of event-related time insufficient as soon as one considers how something exists in reality. Common sense has it: There is a complemenrary notion: elapsed time.

Einstein is often quoted having said: "Time is what the clock reads". Nobody can read future time. Any clock shows always only past time.

Eckard

John M,

You often argued that the future becomes past because the earth rotates. Let me object to a second flaw in this utterance. How fast the earth rotates does measurably depend on influences, if for instance the shape of earth changes because the ice at its poles is melting. The measure time is independent from what gave rise to introduce the notion time. Please don't take my corrections amiss.

If clocks are running equally fast then this is not based on any permanent exchange of information between them but we have little reason to doubt that this quality is inherent to the universe.

Eckard

Eckard,

Actually what I said is tomorrow becomes yesterday because the earth turns. This is not any general reference to future or past, but a specific, common occurrence and the effect creating it.

Time is an effect, not foundational, so possibly a way to understand it is as it functions.

As I relate it to the concept of temperature, consider how you would perceive temperature. You know it is energy being transmitted as the rate at which lots of molecules and even their atomic basis are vibrating and so shedding energy. In a pot of water they are also moving about.

Now in this perception, did the idea of change and thus time necessarily occur? I would say not necessarily. There is just the impression of activity in a particular frame.

As change does occur, how would you measure it? There could be lots of methods. If you could attach a meter to each molecule and record every vibration, that would be one way. You could record the rate steam leaves the pot, or the slowly declining weight of this body of water, as it boils away.

Now all that is really occurring is changes of state. Energy and water radiated or evaporated and gone elsewhere. Stuff moved about. None of this occurred in some extra dimension. It all happened in the present. One set of relations evolved into another.

So this state of the present moves from one configuration to another. We think of it as the present moving from past to future, but it was actually these changes occurring in the present, so it is they which go from being potential, to actual, to residual.

Neither past or future physically exist, because they are not present. It is only our sense of memory and continuity which makes this complicated, since we are like just one of those molecules of water, bouncing from one encounter to the next, in what we experience as a single sequence of events and our memory is that record of encounters we experienced. So we have this sense of moving from distant past events to recent past events and think of it as then moving to future events, but past is residual and future is potential, so it doesn't make sense to think of it as moving from residual to potential, but then we have forgotten all the past possibilities that didn't happen and only remember what did actually occur and so those past events now seem more real than they are, given the physical material moves to other events and there is only the dust and smoke of memory, as these events move ever further into the past, driven by that continuous activity of what is present.

Hope this helps some.

Regards,

John M

John M,

Davies doesn't call time an effect. Perhaps you are at best one of very few people to believe so. I rather understand elapsed time as the measurable delay between a moment A attributed to a cause, and moment B attributed to its effect. This distance is always positive if counted from B to A. In so far, elapsed time is indeed similar to temperature which also has a natural absolute zero. Units of elapsed time are arbitrarily chosen as also are units of temperature. Both scales are reasonably considered continuous (IR).

However, the natural zero of elapsed time, i.e. the actual moment cannot be pinpointed at a particular moment, and intervals of time can endlessly be added. When Newton imagined God winding up again and again his big clock the universe, he attributed God as the cause to time. Your idea of time as an effect of motion like temperature provides a still naive but already less mystical explanation of obvious simultaneity. I doubt that such speculative analogy is of any use. Instead it might be necessary to clarify how event-related and now-related time relate to each other and to reality. Doesn't a question become foundational if something of relevance can be based on its solution?

Regards,

Eckard

Eckard,

Physics values precision over explanation, so measurement matters more than what is being measured. What is being measured are particular events that come into being and dissolve, but what creates them is that underlaying process and energy. Remember energy is conserved, even if it doesn't have some exact shape or form. So the present is that energy, but all that can be measured is the form it takes. So measures of time are that energy transitioning/evolving from one form to another. Duration is just what the energy is doing between one event and the next.

As I argued in the recent contest, not only is reality that dichotomy of energy and information, but it manifests in our physiology, with a central nervous system to process information and the digestive, respiratory and circulatory systems to process energy. This then manifests on many aspects of our social functions, with academics and other thought based disciplines largely concerned with products of the information process and thus distinctions, more than the dynamic creating them. So there is a natural bias toward platonic ideal forms, even though they are evidently emergent. Since we can't measure the basis, the reductionist position is to just ignore it. "Shut up and calculate."

Regards,

John M

Steve Agnew,

On Sep. 13, 2014 @ 00:18 GMT you stated in Why Quantum:

1) There is a past because we have a memory of it, and so the matter of our memory represents an object of past time.

2) All objects represent past time and that is called proper time.

3) The present moment is just as you [John M] suggest, the second dimension of time, action time.

4) The future only exists as the possibilities of an object and there is no single future that is certain.

While I am aware that mainstream physics postulates a fatalistic closed block of time and space which is the opposite of (4), I as an engineer cannot see any good reason to perform Fourier analysis of a signal by an integration that includes not yet existing in reality future data.

Writing in (1) "there is a past because" you did perhaps mean "there is a past, we know it because". I understand the past as something objective. As Shannon explained it, past processes are unchangeable but in principle measurable. I accept that you used the word "memory" for what I prefer calling material "traces".

Your interpretation in (2) of past time as proper time is close to my view that elapsed time includes all past and has therefore a natural point of reference, the actual moment. Presumably, you are still following the convention to count time increasing from earlier to later. Elapsed time counts in opposite direction, and it doesn't relate to an arbitrarily chosen event.

When you used the expression "proper time" in (2), did you distinguish it from coordinate time in the sense of SR?

The "action time" that you introduced in (3) seems to be meant as an actual value at the scale of conventional time. Aren't you aware that conventional time is block time?

I agree on that the conventional time scale is insufficient as to describe reality. However, if you dare introducing a point on a scale that is moving relative to it as a dimension, then I would expect you to clarify what the notion dimension does mean in physics. Orthogonality?

I consider Fig. 1 of my essay 1364 a more radical alternative that clearly reveals how the abstract block time differs from original reality.

Eckard

For some reason years ago I bought a book from a library sale for an old corporate research lab in physics-- Geoffrey M. Dixon's Division Algebras: Octonions, Quaternions, Complex Numbers and the Algebraic Design of Physics.

The idea seemed so simple. The Universe is made of distributed information systems, which follow the basic law of the Universe: Whatever's been created, can be destroyed.

I keep scanning the book for high school student level reading, but can find none. Turning the pages is like looking at a kaleidoscope. I'm blinded by spinning fibers of light and color. They draw me closer and closer the faster I turn the pages of the book. The pages spin like a wireframe water wheel, in an architecture of glittering mathematical intricacies.

Clearly, there was structure enough here, and a clear description of how one creates systems from parts, without damaging any of the parts.

And, how one can destroy a system simply by disassembling it, part by part, without damaging a single part.

For example, multiplying would be a model for assembling a system. Dividing would then be disassembling the system, very cleanly, by factoring a part away.

Each part was never harmed during assembly.

And each part was never harmed during disassembly.

That was all of the story I needed. Dixon had handled all the details.

And now it seems the same has happened in string theory.

So it seems

The Universe isn't made of particles and neither is it made of strings.

The Universe is made of systems that can be nondestructively assembled and disassembled into parts.

The Division Algebras model this kind of Universe in terms of multiplication and division.

cannot be fully encompassed/modeled within the context of an inherently static information paradigm, no matter how small the scale, or complex the pattern.

All of this is the context for Time.

As illustrated by the Twins' paradox from Relativity, the data show each thing has its own time. And in such a context it would be easy to install more structure into Time (for further mathematical analysis)--

Now = ( theUniqueMonadOfTime, Now )

where

theUniqueMonadOfTime = ( nonstandardPast, standardPresent, nonstandardFuture)

("nonstandard" per Abraham Robinson's book.

"non-wellFoundedSets" in Vicious Circles by Barwise and Moss)

And,

Each thing that exists has its own Now.

(Later the Nows will be linked together by various gearing interactions between relative possibilities.)

The process is "unfolding."

Unfolding a Now, we find aUniqueMonadOfTime, and the Now is like a flower--

The flower unfolds, but all the while, it is still one and itself, never stopping being the flower it is during the entire unfoldment.

Unfolding a "Now," you, the being, are at each instant always within the same Now, as long as you exist. So when you unfold a Now, Now stays with you throughout the entire process. That is to say, as something that exists in the Universe, you have to yourself a unique experience of unfolding your Now.

Each cycle of unfoldment may reveal a UniqueMonadOfTime, if you are so lucky as to maintain existence in the Universe.

After all, anything created, can be destroyed in a very clean fashion, as above.

But in this Universe, my awareness of Now unfolds into UniqueMonadsOfTime, one after another in a stream of unfoldment...

"UniqueMonadOfTime"

"UniqueMonadOfTime"

"UniqueMonadOfTime"

And so on.

While for each Unique Monad, I am aware of experiencing Now as always being itself within me, being for me the same and unchanging throughout the process of unfolding UniqueMonadsOfTime, for each thing that exists in the Universe.

Lee,

Time is how we experience this process of assembly and disassembly. Since we are only one point of perspective, we frame this process into a continuum of events and so we think of it as this now moving from past to future, yet it is these configurations being created and dissolved which come and go, so it is actually the future becoming past. To wit, it isn't the earth traveling some vector or dimension from the event that was yesterday to the event that will be tomorrow, but this planet turning relative to its light source which creates and dissolves these events called days.

As you say, each event is an unfolding, a blooming. Like the previous event was the seed casing from which the current event springs. That is because the energy is leaving that prior event, like the energy leaves a day, as the sun moves around to other's sunrises, so it fades from ours, as the new one gathers force. We think of one event leading to the next, but this sequence isn't causal. Yesterday doesn't cause today, but simply precedes it. Energy is causal. Light shining on a spinning planet causes these events of our perception called days. and it pours into us from all directions and we radiate it back out in all directions. It is just that we are mobile organisms and not plants, so we think of direction and momentum as being more elemental than they are, so we like sequence and narrative as explanations. Nature is much more thermodynamic.

Regards,

John M

I get the idea from Dixon's work on the normed division algebras that more basic than particles, waves, or strings are *systems* made of parts, which can be assembled (by multiplication) and disassembled (by division). But this still leaves us with the parts to think about. I will make the attempt!

I get the idea from Barwise's work on non-well founded sets that a formula for time which is maybe more intuitive, but less amenable to calculation, would be the stream Now = (monadOfTime, Now). Where by "monadOfTime" I mean Abraham Robinson's nonStandard monad. MonadOfTime has a central standard point and a halo of nonStandard points. To be compatible with the received model of time as point moving on line, in front of the standard point in the monad there must be a halo of nonStandard points I've taken to calling the nonStandardFuture. And behind the standard point in the monad there must be a halo of nonStandard points I've taken to calling the nonStandardPast. Which in effect posits a tiny room of time that accompanies each system (something different than a manifold).

After thinking about it I have to admit that assembly and disassembly of systems comprised of parts is not really the creation and destruction of the parts themselves. Some more thinking about it--

From Herbert Green's, student of Max Born, book Matrix Mechanics I get the idea that complex numbers in quantum physics

represent possibilities.

Again from Barwise (Information and Impossibilities), I get the idea that a possibility is really a possible *state.* I now realize that when I say that a system comprises parts, I most likely connote that the "parts" are "particles." But that would be wrong. The parts involved are really *states." Further a system of states is really itself a state (actually, a "possible state" or a "possibility").

Now back to creation and destruction of system parts. I wonder if what I'm seeing inside the above tiny room of time for each system is what's called "wave function collapse" in the Schrodinger picture (where the wave function changes continuously in time). However to visualize the collapse I have to see it by looking at the Heisenberg picture, where the wave function is constant in time. Here's the idea:

The Born rule is a map from a complex number to a real number:

c -> r r

time has only a math exitence, see www.fopi.infoAttachment #1: 1_On_the_origin_of_the_observer.pdf

Things happen. Real things, occur. Real things, endure. Real things, happen.

Time is not a real thing.

What actually happens, is that duration elapses. Our clocks measure duration elapsing. Our conscious experience is of duration elapsing.

The Earth`s rotational motion is the fundamental physical mechanism responsible for maintaining our confusion over the true nature of time.

We do have motion in our timeless universe.

Feynman Wrong about the Twin Paradox

Tim Maudlin: "...so many physicists strongly discourage questions about the nature of reality. The reigning attitude in physics has been "shut up and calculate": solve the equations, and do not ask questions about what they mean. But putting computation ahead of conceptual clarity can lead to confusion. Take, for example, relativity's iconic "twin paradox." Identical twins separate from each other and later reunite. When they meet again, one twin is biologically older than the other. (Astronaut twins Scott and Mark Kelly are about to realize this experiment: when Scott returns from a year in orbit in 2016 he will be about 28 microseconds younger than Mark, who is staying on Earth.) No competent physicist would make an error in computing the magnitude of this effect. But even the great Richard Feynman did not always get the explanation right. In "The Feynman Lectures on Physics," he attributes the difference in ages to the acceleration one twin experiences: the twin who accelerates ends up younger. But it is easy to describe cases where the opposite is true, and even cases where neither twin accelerates but they end up different ages. The calculation can be right and the accompanying explanation wrong."

Einstein also taught that the youthfulness of the travelling twin was due to the turn-around acceleration:

Dialog about Objections against the Theory of Relativity, 1918, Albert Einstein: "During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4."

John Norton teaches the same story:

John Norton: "Then, at the end of the outward leg, the traveler abruptly changes motion, accelerating sharply to adopt a new inertial motion directed back to earth. What comes now is the key part of the analysis. The effect of the change of motion is to alter completely the traveler's judgment of simultaneity. The traveler's hypersurfaces of simultaneity now flip up dramatically. Moments after the turn-around, when the travelers clock reads just after 2 days, the traveler will judge the stay-at-home twin's clock to read just after 7 days. That is, the traveler will judge the stay-at-home twin's clock to have jumped suddenly from reading 1 day to reading 7 days. This huge jump puts the stay-at-home twin's clock so far ahead of the traveler's that it is now possible for the stay-at-home twin's clock to be ahead of the travelers when they reunite."

Feynman, Einstein and Norton are wrong of course but the problem is more serious than that. We all live in a schizophrenic world where the youthfulness of the travelling twin is due to the turn-around acceleration, on the one hand, and is not due to the turn-around acceleration, on the other:

Don Lincoln: "Some readers, probably including some of my doctoral-holding colleagues at Fermilab, will claim that the difference between the two twins is that one of the two has experienced an acceleration. (After all, that's how he slowed down and reversed direction.) However, the relativistic equations don't include that acceleration phase; they include just the coasting time at high velocity."

Gary W. Gibbons FRS: "In other words, by simply staying at home Jack has aged relative to Jill. There is no paradox because the lives of the twins are not strictly symmetrical. This might lead one to suspect that the accelerations suffered by Jill might be responsible for the effect. However this is simply not plausible because using identical accelerating phases of her trip, she could have travelled twice as far. This would give twice the amount of time gained."

Pentcho Valev

Abc2000ro: "Why is Einstein solution to the twin paradox different from the one on the internet? The solution to the twin paradox found on the internet is that the twin on Earth is on 1 frame the entire journey, while the twin in space is in 2 frames for the duration of the journey. However, in his own paper:

http://en.wikisource.org/wiki/Dialog_about_Objections_against_the_Theory_of_Relativity

Einstein gives a totally different explanation. He says that what matters is the moment of acceleration. So even if the acceleration happens in 1 second from 0 to 290.000km/s that's the only second that truly matters. So if Einstein says like this, how can anyone bring other explanations? (...) You can talk about the frame switching without saying anything about acceleration. You just draw 2 lines in a Minkowski diagram and that's it. Then you just apply the equations of special relativity and presumably you obtain the correct result. But Einstein says otherwise. That you have to use the equations of general relativity for the moment of acceleration (even though it is only 1 second or 1 year) and only then you obtain the correct results. So who should I trust?"

Abc2000ro asks the fatal question. Einstein was well aware that, unless the acceleration ("gravitational potential") camouflage is used, the clock (twin) paradox is an obvious absurdity:

Dialog about Objections against the Theory of Relativity, 1918, Albert Einstein: "During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4."

Nowadays most Einsteinians do not understand the problem but clever (even though dishonest) Einsteinians do:

Introduction to Classical Mechanics With Problems and Solutions, David Morin, Cambridge University Press, Chapter 11, p. 14: "Example (Twin paradox): Twin A stays on the earth, while twin B flies quickly to a distant star and back. Show that B is younger than A when they meet up again. (...) For the entire outward and return parts of the trip, B does observe A's clock running slow, but enough strangeness occurs during the turning-around period to make A end up older. Note, however, that a discussion of acceleration is not required to quantitatively understand the paradox..."

Pentcho Valev

The twin paradox has a simpler (one way) version in Einstein's 1905 paper:

ON THE ELECTRODYNAMICS OF MOVING BODIES, A. Einstein, 1905: "From this there ensues the following peculiar consequence. If at the points A and B of K there are stationary clocks which, viewed in the stationary system, are synchronous; and if the clock at A is moved with the velocity v along the line AB to B, then on its arrival at B the two clocks no longer synchronize, but the clock moved from A to B lags behind the other which has remained at B by tv^2/2c^2 (up to magnitudes of fourth and higher order), t being the time occupied in the journey from A to B."

SCIENCE AT THE CROSSROADS, Herbert Dingle, p.27: "According to the special relativity theory, as expounded by Einstein in his original paper, two similar, regularly-running clocks, A and B, in uniform relative motion, must work at different rates. (...) How is the slower-working clock distinguished?"

Dingle's question is rhetorical - the slower-working clock cannot be distinguished on the basis of Einstein's 1905 postulates alone. The postulates entail that, as judged from the respective system, either clock runs slower than the other. That is, for an observer in the moving clock's system, the stationary clock at B lags behind the moving clock; for a stationary observer, the moving clock lags behind the stationary clock at B.

So Einstein's famous conclusions that made him a superstar, "moving clocks run slow" and "travel into the future is possible", are based on two flaws. Initially Einstein advanced his false constant-speed-of-light postulate, which allowed him to validly deduce that:

moving clocks run slow, as judged from the stationary system.

Then he illegitimately dropped the second part of the above conclusion and informed the gullible world that:

moving clocks run slow, that is, travel into the future is possible.

Pentcho Valev