02 December 2013

Why Time Travellers Never Turn Up To Dinner

Many physicists accept the notion that wormholes to the past exist in quantum foam. This implies that the past exists, independent of what the observer views to be the present. 

Unfortunately much time and thought is wasted on the question of physical time travel to the past via artificially enlarged wormholes and subsequently even more time and thought is wasted on the question of temporal paradox, stemming from the hypothetical supposition that a chronologically linear series of events (a.k.a. a "timeline") is universal and immutable. The impossibility of a temporal paradox, we are told, proves that time travel itself is impossible. 

The only real temporal paradox here is that grown, intelligent human beings can believe in the existence of wormholes to the past (however tiny) and at the same time claim that the universe can only contain one immutable timeline. 

To elaborate: the classic hypothetical temporal paradox is the question, "What happens if travellers to the past kill their own ancestors, thus preventing their own birth?'"

"Impossible!" theorists declare, "because then the time travellers would never have been born in the first place, and subsequently would not be around to perform such an act, a fact which in itself would paradoxically guarantee that the time travellers in question would indeed be born blah blah blah."

These theorists seem to forget that a small enough particle (using a wormhole in the quantum foam) could do something similar to our disturbingly murderous time travellers on a smaller yet nevertheless equally real scale. In fact it's probably happening all the time. 

The question of temporal paradox is easily resolved: when the past becomes the present a new and independent timeline is established. Any actions taken to alter history can only affect the newly established timeline. The homicidal time travellers may slay their ancestors in the past, but once they have returned to the "present" in their original timeline (assuming they are able to) their actions will simply never have taken place. In other words, the immutability of a chronologically linear sequence of events is relative and not universal.

That is why nobody turned up to that party Stephen Hawkings threw for time travellers from the future: they did go, just not to the one in our timeline. 

But these questions of physical time travel are, in my opinion, the least worthy of our consideration when we entertain the notion that the past exists, as this has far more important and far-reaching implications regarding the nature of the universe and our own existence within it as conscious individuals.


The Living* 

People whose spatiotemporal parameters are currently converged with our own. 

The Dead* 

People whose spatiotemporal parameters have diverged from our own. 

The Unborn* 

People whose spatiotemporal parameters have yet to converge with our own. 


A convergence of spatiotemporal parameters. 


A divergence of spatiotemporal parameters. 

*All these terms are relative.

The Big Time Loop

From Wikipedia:
Eternal return (also known as "eternal recurrence") is a concept that the universe has been recurring, and will continue to recur, in a self-similar form an infinite number of times across infinite time or space. The concept is found in Indian philosophy and in ancient Egypt and was subsequently taken up by the Pythagoreans and Stoics. With the decline of antiquity and the spread of Christianity, the concept fell into disuse in the Western world, with the exception of Friedrich Nietzsche, who connected the thought to many of his other concepts, including amor fati.  
In addition, the philosophical concept of eternal recurrence was addressed by Arthur Schopenhauer. It is a purely physical concept, involving no supernatural reincarnation, but the return of beings in the same bodies. Time is viewed as being not linear but cyclical.  
The basic premise proceeds from the assumption that the probability of a world coming into existence exactly like our own is greater than zero. If either time or space is infinite, then mathematics tells us that our existence will recur an infinite number of times.
If we accept the position that the past exists and add to it the notion that the immutability of any chronologically linear series of events is relative rather than universal (ie that parallel timelines can exist) then there is no necessity for either time or space to be infinite in order for "eternal recurrence" to occur. In effect, the universe could recur an infinite number of times simultaneously within its own finite spatiotemporal parameters. 

In this scenario, the observer is only able to be consciously aware of one recurrence at a time, because memories are physically stored in the brain and therefore possess their own spatiotemporal parameters (which is why most of us don't remember what we did tomorrow). Were the observer granted the ability to remember each recurrence, he or she might erroneously form the opinion that there was a sequential order to those recurrences, when in fact they were concurrent. This is the 'Big Time Loop', known elsewhere as the Multiverse
The multiverse (or meta-universe) is the hypothetical set of infinite or finite possible universes (including the historical universe we consistently experience) that together comprise everything that exists and can exist: the entirety of space, time, matter, and energy as well as the physical laws and constants that describe them. The term was coined in 1895 by the American philosopher and psychologist William James. The various universes within the multiverse are sometimes called parallel universes. 
The timelines and concurrent recurrences that make up the Big Time Loop equate to the parallel universes of the Multiverse.

Omnia mutantur, nihil interit

In the film Groundhog Day, Phil Connors (Bill Murray) experiences the same day over and over again. The most implausible aspect of the story is not that the character is caught in a time loop - the universe (as described in this post) is itself one huge time loop - but that the character is able to remember previous recurrences. If he wakes up in the same identical physical state every morning, then the parts of his brain that store memory should do so too.

Having said that, Groundhog Day is still by far and away my favourite example of time travel in film, as it is one of the few movies involving time travel that manages to avoid the "universal timeline" paradigm that is employed all too often by Hollywood.

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