Shared awareness is an implication from the philosophical theory of Transworld identity, which claims that many identical copies of a mind may exist in many different universes (perhaps an infinite number). However, all identical minds may share the same awareness, no matter how far separated they are.
This shared awareness may be "stronger" if there are more mind copies across reality. The awareness won't feel any stronger, but an observer is more likely to find their mind to be of a common type than of a rare type. This is similar to the anthropic principle, which claims that other universes exist, but most universes don't generate as many human-like observers as our universe. Ours is said to be unusually effective at generating human-like minds, which is why we find ourselves here. No one knows if this is true, and anthropic theories are much criticized.
Shared awareness is a notable and necessary implication of the Many Worlds Interpretation of quantum physics. It helps demystify the strangest aspect of quantum mechanics, at the cost of creating many new universes.
The best known explanation involves Schrödinger's Cat. According to the conventional Copenhagen Interpretation of quantum physics, it may be possible for a cat to be alive and dead at the same time, if it's confined inside a perfectly sealed box that allows no information to leak out (such a box could probably not be constructed). Only by opening the box, and "collapsing the wave function", would the cat be revealed to be either alive or dead.
In one version of the Many Worlds Interpretation, the entire universe is constantly "splitting" into new parallel universes. In half of them the cat could be alive, in the other half dead. However, the observers of the box, who don't know what's inside, remain identical in both types of universes. There would be no way to distinguish between them even in principle, so their awareness would also remain united; at least until the sealed box is opened. It would be a shared awareness.
This remains unproven however. In other versions of the Interpretation, the observers wouldn't even "split" until the box is opened. If the laws of physics are like a computer program, the same "code" might generate both types of observers. In fact all identical phenomena across the universe could be generated by one single process for that phenomenon. In still other versions of the Interpretation, all parallel universes already exist at the outset. Regardless, each common version of the Many Worlds Interpretation has been shown to make the same predictions as all other accepted interpretations of quantum mechanics, so the Interpretation might be true.
Quantum physics only works in universes with the same laws of physics as ours. Shared awareness could extend to the much larger philosophical Multiverse, as in Tegmark's mathematical universe hypothesis, which allows for many different laws of physics.
Anthropic awareness theories are often discussed on the Less Wrong web forum. A well-known example is quantum suicide, which has even inspired works of fiction. Equally well known is the theory of ancestor simulations, which claims that our world is probably a computer simulation. Less Wrong contributors have theorized that someone's likely identity can be manipulated by creating many copies of someone's mind, as in Roko's Basilisk, a theory which some members consider dangerous to know about. All these theories are much disputed.
What they have in common is that observers can't know which possible universe they inhabit. The majority interpretation at Less Wrong and elsewhere is that a single shared awareness inhabits all copies of an observer in all universes, but not with the same probability. Just by understanding Roko's Basilisk, you could make it a larger percentage of your reality. A minority interpretation at Less Wrong is that all possible minds are equally likely to exist.
Shared awareness is also a possible solution to Newcomb's Paradox. In this paradox, there are two boxes that both contain the same (small or large) sum of money. A participant can choose to take only one box or both. However, a superintelligence will somehow accurately predict the participant's decision before placing the money in the boxes.
If the participant chooses to take only one box and leave the other, both boxes will contain a large sum of money. If the participant chooses to take both boxes, the superintelligence will have predicted that, and they will both contain only a small sum of money. The paradox in this case is that the participant will be better off taking only one box, knowingly leaving a large sum of money on the table.
Multiple people who have considered this paradox have concluded the only way the superintelligence could predict the participant's decision is by fully simulating the participant's mind in advance. That means the participant in such an experiment would have a shared awareness with their simulation. They would literally be both at the same time, and by deciding whether to take one box or both, they would also decide how much money they contained. This remains a minority interpretation however.
Shared awareness could reduce the impact of the philosophical concept of Eternal Return. It may be meaningless to say that everyone will be recreated by pure chance to keep reliving the same life an endless number of times in the endless future, if all these lives are only experienced once. In that case awareness could transcend time.
The theory of shared awareness is related to a derivative of Leibniz's Law, known as the Identity of Indiscernibles, which says that if A and B are completely identical, then A IS B. It may be impossible to prove that two identical brains share the same awareness. However, there would be no way for the brains to distinguish their awareness.
Under the anthropic principle, each observer could treat their own existence as a statistical sample of everything that exists. Observers will tend to find their awareness to be more probable than most other possible minds of the same complexity, which are less likely to exist. However, they can never know the exact process that created them, as there may be countless ways to create any mind, in which case it might not matter. In the future, this could be useful for mind uploading or mind backup research, implying that a computer simulation of a person could continue that person's awareness.
Different types of shared awareness are named and described in the "Aware Theory wiki", a website containing original research that attempts to describe how identical and similar structures across reality may generate interfering forms of awareness. The site assumes that awareness can be described as changes in material patterns, but that all instances of such patterns must be considered to explain its nature.
The hypothetical minds listed in the wiki all share the made-up term "Ixperiencitness", and there are hundreds of other neologisms for other types of shared awareness.
The wiki also seeks to outline ways how awareness may "flow" from a mind to its closest continuer.
- External link: http://awaretheory.com/
An opposing view is David Lewis's counterpart theory, which holds that identical objects and minds in other universes should be considered distinct from each other. That could deny the possibility of shared awareness.
A more standard belief is that everyone's awareness is fully dependent on this universe, and that once they die here, their awareness can no longer exist and may be gone forever. This view is held by many atheists, and Isaac Asimov said that this insight had removed all his fear of death.
- Stanford Encyclopedia of Philosophy, Aug 8 2013. https://plato.stanford.edu/entries/identity-transworld/
- Stanford Encyclopedia of Philosophy, Identity and Individuality in Quantum Theory, Aug 3 2015. https://plato.stanford.edu/entries/qt-idind/
- example: John Archibald Wheeler, the One-electron universe, 1940. http://io9.gizmodo.com/5876966/what-if-every-electron-in-the-universe-was-all-the-same-exact-particle
- Many Worlds Theory blog, Matthew Rave, Nov 12 2012. https://manyworldstheory.com/2012/11/12/misconceptions-about-the-many-worlds-interpretation-of-quantum-mechanics/
- Quora question, May 2014. https://www.quora.com/Does-any-interpretation-of-quantum-mechanics-offer-testable-predictions-that-differ-from-other-interpretations
- Omicsgroup.org wiki article, retrieved Jan 10 2017. http://research.omicsgroup.org/index.php/Quantum_suicide_and_quantum_immortality_in_fiction
- Wikipedia article deletion log. https://en.wikipedia.org/wiki/Wikipedia%3AArticles_for_deletion%2FQuantum_suicide_and_quantum_immortality_in_fiction
- Eliezer Yudkowsky & blog discussion, Jun 12 2008. http://lesswrong.com/lw/r8/and_the_winner_is_manyworlds/
- Franz Kiekeben, 2000. http://www.franzkiekeben.com/newcomb.html
- Hpindiogine (Fall 2006), referring Andrew Gelman (2006). https://hpindiogine.wordpress.com/article/newcomb-s-paradox-1g2r8go4ti4mm-33/
- LessWrong discussion, Anonymous23, Feb 1 2008. http://lesswrong.com/lw/nc/newcombs_problem_and_regret_of_rationality/
- Popular Science, May 16 2014. http://www.popsci.com/article/science/neuroscientist-who-wants-upload-humanity-computer
- from the site (Nov 10, 2017) "The I experience it test determines if some other body produces a consciousness that you experience. The exact same structure and functioning in a different brain will pass the same ixperiencit test for you. As will a very large amount of closely approximate structures and functionings."
- Deutsch, Harry (Summer 2002). Edward N. Zalta, ed. "Relative Identity". The Stanford Encyclopedia of Philosophy. Retrieved 6 October 2014.
- "Paul B. Kantor "The Interpretation of Cultures and Possible Worlds", 1 October 2002". Retrieved 6 October 2014.
- quoted by John Altson, in "What Happened to Grandpa? A child views the hereafter through the world's major religions" (2009). https://todayinsci.com/A/Asimov_Isaac/AsimovIsaac-Fear-Quotations.htm