Human awareness remains a bit of a mystery. It hasn't been absolutely proven that some form of awareness could not exist in a different form after brain death.
This strange intuition motivates most religions and cryonics firms. But is there any reason to believe it could be true?
Pythagoras was the first to imagine a more scientific approach. Everything can be described as a number, therefore everything is a number - including human awareness at any point in time. And numbers are of course immortal.
Nietzsche's theory of eternal recurrence states that atoms are eternal. They will forever keep rearranging themselves throughout the universe in all combinations, until every possible life-form has been recreated by chance. You have already read this sentence an infinite number of times.
Both theories rely on rather obsolete physics with mystical elements.
The Physics of Immortality by controversial physicist Frank J. Tipler is set in the distant future. He presumes technology will continue to improve forever. When the universe is about to collapse back into a super-tiny point, information management will suddenly get much easier. Increasingly complex patterns will then be 'embedded' in the implosion, multiplying without limit. There will be an infinite number of particle collisions in a finite time. Enough resources will become available to recreate every mind that has ever existed, including yours at this exact moment.
All the problems and annoyances that we suffer today will not be recreated, however. It will be a scientific version of heaven. The last moment of time will be an eternal new beginning instead of the end of everything.
Tipler assumed that advanced civilizations would likely be benevolent, but would they really?
It's true that as societies mature their ethical awareness improves, but that may be a uniquely human phenomenon. A sufficiently advanced civilization might literally transcend ethics. Once it fully understood the patterns forming a certain emotion, it might no longer consider that emotion to be meaningful.
More recent discoveries have ruled out this version of Tipler's theory. It seems there won't be a 'Big Crunch'. Instead the universe will expand forever, all matter to be diluted away. Even electrons may disappear, giving up their energy to space itself.
However, this does not affect the basic premise: human consciousness may not be as ephemeral as once thought. Patterns have a way of recurring in nature, from snowflakes to proteins to stars.
The human mind is synonymous with the arrangement of neurons in the brain. About a trillion cells are connected by quadrillions of tiny wires, which can be 'on' or 'off' (usually the latter).
While staggeringly intricate, that pattern is much less complex than the atomic description of even a single grain of dust. A lifetime of experience could be described by 10 to the 30th (nonillion) bits. A yet-to-be-invented atomic recording medium could theoretically store this lifetime's worth of awareness inside a shoe box.
The human mind is not as complicated as it likes to believe. The precise mechanism of thought remains beyond understanding, but compared to the complexity of the universe it's not particularly remarkable.
That doesn't mean minds will be easy to replicate. So many patterns are possible there's not the slightest chance of finding two identical snowflakes or mental states in the observable universe. The universe is much too small for that to happen.
We also know from brain injuries and dementia patients that consciousness can fade away. Why shouldn't it disappear altogether?
The answer must involve other universes. It's an increasingly popular notion: other versions of Earth, where the Roman Empire survived to this day, or where civilization flourished in central Africa.
Most versions of Heath Ledger are still alive, the War On Terror is a strange anomaly, and the aliens have already arrived in many places.
There will also be many people who miraculously survived whatever killed them in this universe. There are even places were immortality was discovered by pure chance. Some future versions of ourselves (with all memories and personalities intact) will always manage to defeat death, using unimaginable technology, pure luck, or strange physical laws.
In such a 'Multiverse' no one has to die. Somewhere, someone always survives. These people could even be called our descendants. For every mental state, including our final one, there are countless possible descendants.
Unfortunately, most descendants will be strange. Necessarily emerging from unusual circumstances almost certain to change them, they could have alien characteristics along with our more familiar ones. Whatever brought them into being would have added many new traits. Their new existence might be incompatible with human concerns.
Some descendants are stranger than we can imagine. Consciousness is pure information. Most descendants could be Boltzman Brains, chaotic patterns emerging momentarily inside a larger structure. The plasma pattern in the center of a distant star could momentarily form a perfect representation of a conscious mind. Perhaps every pattern can be regarded as being remotely conscious in this way.
Because of the 'user illusion' minds don't care what medium contains them. Different fragments of consciousness could even self-assemble across space and time.
Parallel universes are exactly as tangible as unicorns and dragons. They have no apparent effect on our daily lives. Why should they only become relevant after death?
Universes could cancel each other out. Maybe the mathematical descriptions of most parallel worlds add up to exactly nothing, leaving only present reality.
People who share this world are closer than they are to their own remote 'descendants'.
Human perception is based on the assumption of a singular unique self. Expanding this reference frame will be more shocking than death itself.
Most possible resurrection schemes are at least somewhat unlikely. They create observers who occupy a shrinking fraction of reality, sometimes dramatically so.
Still, what other hope exists? The anthropic principle claims that whatever strange perceptions remain after death become the new reality by default.
Minds that vanish into oblivion won't have any perceptions, so they aren't real. They can't experience non-existence.
Our universe can probably be described by a simple equation, but that would no longer be true for most possible universes, both random and organized. Our current existence is far more probable than the best and most popular immortality scenarios.
If consciousness does continue without end, our most likely descendants will probably be created by near future civilizations:
When considering parallel universes, it's important to remember the principle of mediocrity. What matters is not what's possible, but what's probable.
Statistically, most possible (but not most actually enumerated) descendants should be infinite. There are ever more ways to arrange a pattern as the file size increases. That doesn't mean the larger, more complex descendants will outnumber the smaller ones. Mathematically speaking they are also much harder to describe and generate, and therefore less common. There are vastly more copies of the smaller, simpler descendants.
That's probably the reason why human minds are (very) finite, rather than boundless.
Anyone hoping for a scientific reincarnation should not expect to be much improved. They would probably be recreated by a civilization only slightly ahead of ours, perhaps a direct continuation of ours. For this reason it would make sense to start mind reconstruction foundations and research projects today.
A randomly recreated mind should expect to become aware as early as possible, perhaps as a pioneer in a mind reconstruction experiment.
Perhaps that would be for the best. We couldn't hope to guess the motivations of more distant civilizations. Why would they even bother to recreate a mind from their real or alternate pasts?
Possible reasons might include historical research, entertainment, or part of an effort to create a complete theory of mathematics by generating complex patterns.
They might also need human-level minds to perform relatively simple tasks for incomprehensible reasons. There would be no profound revelations or transcendent meaning.
This theory does not address the problem of identity. An identical copy wouldn't be the same as the original, but that objection may well be meaningless.
Ultimately, reality may be too complex for such speculations. Philosophers often overlook important details. A fully accurate simulation of the 'Multiverse' would have to be just as large as the original.
Our best guess is that people should act as if this life is all there is, but those who fear death will never be able to let go.
Probably the best hard SF novel ever written: Infinite Thunder by Jack Arcalon.
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