Suppose two systems with opposite directions of time and equal degrees of freedom were to interact. What would happen?

Lewis Carroll’s fame is universal. I can easily cite a couple dozen books that mention him or quote from his books. Temptation to quote from Alice’s experiences with which so many people can identify, is indeed great. But the trend may be reversing. In the introduction to a book I have recently come across, the author found it necessary to mention that in the whole of the book there is not a single reference to either Alice in Wonderland or Through the Looking Glass - the two books that made the name of Lewis Carroll a household item the world over. However, his other works are either forgotten or known far less. In real life he was a mathematician C. L. Dodgson with deep interest in symbolic logic and logical reasoning. I have described elsewhere one of his probability and the doublets puzzles.

I always figured that this was kind of like reversing parity and as a result needing to reverse time as well. (I guess the looking-glass world wasn’t antimatter, or Alice wouldn’t have fared so well)

You can’t maintain interacting systems with opposed arrows of time.

Black holes can, otherwise they would not be able to evaporate. IMO Hawking radiation must escape along parrallel surface reflections, allowing it to escape unseen and able to freely interact with each arrow of time; marrying the two together so they seem like a seamless past and escaping up imaginary potentials, as the universe observes the real objects it creates.

I don’t see how they are incompatible, if they are incompatible then that’s because one is from another universe. Which does not mean you can’t make them compatible; esp. if you can convince the other direction your past matches its interactions.

To the extent I consider time a measure of motion, rather than the basis for it, the concept of “now” as a point is meaningless. To actually freeze motion would require a temperature of absolute zero, at which point measureable reality ceases to exist, since measurement requires a degree of interconnectivity and transition, which don’t exist without motion. So since the concept of a point in time can only be approximate, any measurement from or to such a point is equally approximate. To suppose otherwise, you end up with a form of Zeno’s Paradox, where nothing happens, although it is obvious that much happens, as you seem to be hinting at.

If there is no change, then there is no history, no past in time. There may be many molecular or atomic manouvering, permutations for every piece of matter in existence, but look at any single moment anywhere on Earth, and there is a vast amount of change happening, no two “seconds” are identical?

Although the measuring clock is identical, the fact one can go back 13 billion ly’s and find a Universe that has totally changed, means that locally “second_to_second” time NEVER changes, or there is never any recordable evidence to such changes, but Universe_to_Universe Bang_to_Rip, then there a not only vast amount of changes, the local Laws of Physics must have changes emmbedded into every local interaction, like a “new” geometric rubik cube appearing with a new set of rules and regulations?

Gravity for instance has today, “NOW” has four signatures, there are FOUR FOURCE’S two of inner force (short range)we and two that can be demmed outer force (long range), these have been set sometime in the long distant past, just what changes occured to configure Gravity into this sequence, or order of sequence?

What if Gravity was a positive inner force “NOW”, and the strong molecular “now” force, relagated to the Atomic extreme?

Is there a time in the Universe, where all force’s interchange locally?

My point is what is happening in the now that decides among all the potential futures. That which will happen will be what is manifested by the energy of the universe. All other possibilities are the paths not taken. The question is what determines the path that the energy chooses. Often times it is like a meandering stream, pulled by larger forces of gravity, heat and convection, not going fast enough to force a straight path, bouncing off the hard spots, curving around, washing over the small stuff. As I said, if the order of past events is still vital and flexible to absorb new energy and the information it contains, even if it is simply a message of raw force, then the future is in many ways a continuation of past events, but if the old order is too rigid to accomodate fresh energy, this energy pushes the old out of the way and starts a new system of order. The first way is like the passage from spring to winter, as the new grows, aborbing sun, water and minerals, but necessarily becoming more rigid as it gets bigger. The second way is like the passage from winter to spring, as the dried out husk of the old is pushed aside by new life, cracking through where the shell is weak, or brittle. Action and reaction. In terms of current politics, you might say that McCain is winter, Obama is spring and Hillary is somewhere inbetween.

The past has gone, it will not happen over and over again, therefore there can be no change occuring in any system’s past. The only change is the present time? To change the past, is to change the future, think about it, if you changed yesterday in any way, it would certainly have reprocusions for “today”, thus any change of past is a change of the future “today”?

Now we can make statements such as:”There was change in the past”..but how do we narrow it down to “ago”?..how long ago did changes happen?..10seconds ago?…five seconds ago?..1 second ago?..

Truth is, at every instant of “ago” there was change, infact the whole of the past was really changing events, there was never any moment in one’s past wherby no change occured!

This now begs the question of:Will all future events involve “change”?

When you look back at today, from tomorrow, you will notice change, you cannot, repeat cannot!..record events 100%, that is the incomplete nature of Relativity?

But this has been a troubling issue of late for me in terms of this arrow time. The memory issue, the whole works.

Kurt Gödel Time 100

Soon it dawned on a few insightful souls, Gödel foremost among them, that this way of looking at things opened up a brand-new branch of mathematics — namely, metamathematics. The familiar methods of mathematical analysis could be brought to bear on the very pattern-sprouting processes that formed the essence of formal systems — of which mathematics itself was supposed to be the primary example. Thus mathematics twists back on itself, like a self-eating snake. Bold added for emphasis

I see where you’re going with the entropy-only arrow of
time argument, but I don’t think you can keep it strictly
classical and large scale.

*Is* there macroscopic irreversibility? Can it be
proven without resort to quantum? Is only our initial
boundary condition important?

Let’s think about things from the perspective of some
reverse colleagues out there. (This is going to result in
messed-up pronouns; sorry. I’m also not even going to try
to handwave a map between their observational tools and
ours).

Observations of (their) past show a tendency towards
the collapse of cold, randomly distributed gasses and cold
photons into hotter, denser, metastable arrangements that
“sink” heated photons, neutrinos and free electrons into
baryonic matter. Star-forming nebulae coalesce into stars
– the final infall before stellar ignition is sometimes
quite rapid — the stars in turn heat up, fission metallic
elements thanks to free neutrinos and the like, which are
attracted to dense, high-energy objects like stars. Stars
eventually cool and dissolve into nebulae. This is
cyclical, with increasing proportions of lighter elements
released in each star-dissolving cycle.

The best observations of the CMBR and the relative
motions of celestial objects suggest a future big crunch,
which likely will involve only the final hydrogen-rich
diffuse gas that evaporated out of the final cycle of stars.
The end result is likely to be a hot dense gas which will
(similar to stellar fission) break apart atoms and
nucleons into simpler particles. These may in turn form
structures within the plasma, but unfortunately behind the
veil of the final breakdown of baryons, we can only guess
that metastable configurations can’t last very long
because of the heat leading up to the final explosive
infall of the quark-gluon plasma. One big problem about
the future is how the energy that drives the metric
contraction of spacetime can overcome the tendencies of
the hot post-baryosis phase members to resist contraction.

There is another boundary condition strangeness,
namely the highly unlikely distribution of the matter and
energy universe in the distant past. We know from
observation that more objects appear within the limit of
visibility over time; the new material is essentially
homogeneous and arrivals are distributed isotropically
across the sky. Regression suggests that at some point
there was a relatively small amount of very cold matter
within the limits of photon-mediated interactions. That
the combination of the primordial gas (and/or black holes)
fell into metastable large structures is uncontroversial,
since that happens in labs at smaller scales, and at
middle scales in astronomical structures. However, there
is a fine tuning problem with the initial distribution of
causally-connected local matter and energy at the “time of first
infall”.

Back to us… how do we objectively decide which of
these history->future progressions has greater degrees of
freedom? In their view of the universe, the tendency
towards condensation into systems with reduced
availability of microstates is a given, just as the
tendency towards an increase is a given in our stat mechs.

Yes, these are incompatible views. We think that a
tendency towards reducing available microstates is
impossible, they think that it is not only perfectly
natural, but derive that isolated systems always do this.
Each party has an apparent fine-tuning of boundary
conditions that underlie their respective derivations,
with the initial one being critical. Theirs is thermal
equilibrium, which comes to an end thanks to a metric
collapse of spacetime. Ours is a false vacuum fluctuation
which is magnified by a metric inflation of spacetime.

Is their view just backwards from ours, or is it
somehow objectively invalid? Can that be shown without
also showing the presence or absence some underlying
irreversibility in microscopic interactions?

What determines the future is where the energy goes. Usually past order incorporates and adapts fresh energy and the future is a continuation of the past, though sometimes the past is too rigid to incorporate anything new, so energy accumulates elsewhere and the future becomes a reaction to the past. Life incorporates this cycle of growth and corruption through regeneration. Frequently the future is hard to predict because the compass points we tend to take for granted are also adjusting to forces and energies we are not aware of. The result is that what we tend to consider the most durable and and unchanging aspects of our sense of order are also potentially the most rigid and brittle. The consequence is that when we are young, we see and think in terms of objects, but as we get older and understand we were born into one world that is constantly dying off, as another grows up in its place, we learn to think in terms of process. So that by the time our alloted time is up, we see beyond the limits of definition and understand that death, like the absolute, is as much about everything as it is about nothing.

Sam,
Could you imagine space as any less “linked” to the concept of temperature than it is to time? How many arrows of time, such as entropy, universal expansion, gravitational contraction, anthropic aging, atomic decay, etc. are not a consequence of some manifestation of temperature? Yet we understand temperature as a consequence and description of motion, not some dimensional basis for it. As for space, what would you consider as the default description of space, the dimensionless point, or the featureless void? I tend to think it’s the void, yet it seems cosmology and geometry consider it the dimensionless point.

Sean,

An interesting point this discussion brings to mind is that there are natives of South America who consider the past as what is in front of them and the future as behind them. This is because their point of reference, the center of their four dimensional coordinate system, if they used one, is the energy, not the observer. So that the event happens, they observe it and then the information goes past them, thus the arrow of time goes from event to observation. We think of the future as in front of us because we are the center of our coordinate system and we are moving from previous events to future ones, much as the hand of the clock moves from previous time units to future ones.

As the girl said, “Curiosity often leads to trouble.”

Now I’m wondering what you mean by ’share information’… If two directions of influence were flowing, any single instance of time would reflect the predominate direction of influence (usually past to future), but if the information flow from future to past could experience a temporary surge in strength, and/or the information flow from past to future were diminished enough to allow the normally-weaker stream of influence from the future to exert the dominating influence, then a single subjective moment in time might reflect the future moreso than the past. There is no need for the streams of influence themselves to be mutually held in awareness or directly compared. The ‘interaction’ would be a simple summation function that resulted in a single moment of awareness. (Does that make sense?)

Cormac– it’s definitely not consistent! Carroll didn’t try very hard to come up with consistent behavior for the White Queen, even granting the freedom of inventing new laws of physics and logic.

?Living backwards!’ Alice repeated in great astonishment. `I never heard of such a thing!’
` — but there’s one great advantage in it, that one’s memory works both ways.’
`I’m sure MINE only works one way.’ Alice remarked. `I can’t remember things before they happen.’

Both ways? Surely it is not entirely consistent that the Queen’s memory would work in both directions - it implies she is experiencing time both forwards and backwards, instead of a symmetric experience to Alice! For the same reason, her conversation with Alice wouldn’t make sense from her frame of reference…
Or have I missed something?
Regards, Cormac

I’m still a little confused… Are you referring to a system of two individuals (who presumably need consensus in order to communicate), or are you referring to two directions of information flow within a single mind?

I ask because it occurs to me that there might be a survival advantage if a single mind is able to process information outside the arrow of time. For example, let’s say two rather primitive people have chosen to engage in a battle of fisticuffs over a critical supply of food. The winner survives another month; the loser has to find another source of food.

Would it be to the advantage of one of them to be able to deflect the subjective experience of the pain of any injuries sustained into the past, so that it has been processed before the fight occurs, thereby rendering that person less likely to be inhibited while fighting? (The injuries would still occur, however the subjective experience of pain would not follow the injury, but would have already been processed.)

The reverse movie test assumes that the observer’s mental processes aren’t affected by the time-reversed scenario.

The problem with all of the fictional scenarios (I only dipped into this thread, so one of them may have it covered), is that they always assume a conscious observer which thinks using the same arrow of time we do. This allows full use of the novelty effect of the situation.

My point in #18 though, is that this would not be the case in a time-reversed universe. The observer’s thought processes would also be reversed: Mental images would precede their perception. So, to a conscious observer, causality would not appear to be violated and the “reverse movie” would thus look just the same as it does to us.

So I’m suggesting that if the rules of time-reversal are consistently applied, nothing very interesting would be seen at all. What’s at “either end” of time’s arrow in such a universe might be an interesting
question though!

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John F. Kennedy Jr.