Science Fiction and Death
The thing about death is there is no experiment that can determine what happens to consciousness when we die. It is a one-way street and a dead person can't report back anything about the experience or lack thereof.
When the brain dies, we are turned off, like a computer. Consciousness stops. All of our memories are lost due to death of the storage medium, and our personality is lost because the programming dies with our synapses.
This is very upsetting and the vast majority of people over the centuries have found this to be counter-intuitive. It does not seem right that we turn off and that there is no “next” to our lives. We are very used to experiencing something new that follows every event in our lives, and it seems obvious that there should be something following death.
In order to define the “next” thing after death, people have postulated constructs like the wheel of life, ghosts, souls, Valhalla, Hades, Heaven, and Hell. These solutions are either speculation or else hearsay. There is no reliable firsthand knowledge of life after death. Mediums are frauds; there is no experimental evidence of ghosts or spirits.
Religion seems firm on insisting some kind of afterlife. This is based largely on hearsay evidence from writers removed from actual events. Religious belief in an afterlife is the wishful thinking of people who choose not to question the third hand testimony of superstitious writers about remote events.
Faith, however, is an important comfort to many people, and faith is a good choice for most of us. It would be nice, however, if science fiction could reassure the rest of us about what happens after we die.
Science requires a reproducible experiment to prove something. It would require that a person who has died communicate with those still alive, and this must occur in such a way that we could repeat it. One person coming back from death and talking about it is not adequate proof. There are many ways that we can be fooled, and gullible observers from 2,000 years ago might be not be reliable.
Clearly, science is at odds with an afterlife.
Science Fiction on the other hand is speculative. It allows for science-like principles to be applied to real world problems. As long as this sciencefictional approach is reasonable and looks like science, science fiction will offers a way to suspend our belief in what we know and, for the moment, accept a belief in what we might know.
Science Fiction does not require an experiment, other than the Gedankenexperiment performed by the writer's speculation. It is only necessary to provide a process or mechanism that does not severely bend our ability to suspend disbelief. We need to satisfy a science-like explanation of life after death that is more or less reasonable and will allow us to run thought experiments that we can accept as possible.
An obvious approach to this is to write a story where a scientist uses a device or principle to talk to the dead, or better yet, God himself. Unfortunately this is a very weak approach. It is too much of a leap. This would require that God is in and of the universe – that God is subject to and affected by the laws of physics.
There isn't a logical chain of reasoning that arrives at the proof of God. Logical arguments that say, for instance, that since the universe exists that it must have been created, fail because it is circular logic. The universe exists, and there is no evidence to say that it once did not exist. Saying that God created the universe could imply that all things need to be created so that God must have been created, also. To say that God was not created, implies that things can exist without being created, so the universe could exist without being created.
Logic fails us because God is a step outside of logic. God, if he existed, would exist outside of science and the universe. It is not possible to create a scientific experiment to prove there is a God because God is beyond science. The only proof of God is faith. Thomas did not believe until he touched Jesus' wounds. He performed an experiment that is impossible to repeat with unbiased observers, and therefore, is not science.
Science Fiction plots that rely on the discovery of God's home planet, or experimental proof of Heaven, or a radio that can talk directly with the dead, are not believable. They break not only the rules of science, but also the principles of all faith-based religions. Plots about making a machine that can communicate with people in heaven are silly. This kind of thinking demotes God to a big guy with a beard floating around in space.
We are left with non-religious ideas about life after death. In these scenarios, ghosts, the soul, and an afterlife are physical things that obey the laws of physics. They can be natural or the result of invention by humans or other intelligences.
Philip José Farmer's book To Your Scattered Bodies Go describes an afterlife where everyone that has lived on earth since the cave men wakes up on a planet near a large river. The mechanism that lets this happens is controlled by an alien race that records the lives of humans and reincarnates them on the banks of the river.
Van Vogt, Heinlein, Herbert and others, have used reincarnation as a theme. Often the method is not well explained, but it may be that we can think of the body as a computer with some kind of permanent storage that can be retrieved. For instance, Greg Bear, in Moving Mars, uses technology to extract the memories from the heads of people who chose to freeze themselves when they die.
Moving a person's personality and memories into a computer has become a cliché in SF, to the point where editors are reluctant to even publish these kinds of stories.
I remember a story where aliens observed the earth from a great distance. Just as the CIA can read the contents of your computer through your window by recording the electromagnetic waves given off, these distant aliens recorded the memories and thoughts of humans across a gap of thousands of light years and reproduced some of them long after they had died on earth.
Similarly, time travelers from the future might send back recorders to save the souls of those who have lived in the past. Spider Robinson used this in one of his stories. Wilson Tucker used something similar in The Lincoln Hunters to reincarnate Abraham Lincoln.
Although there has never been believable evidence of ghosts, there may be mechanism where the electromagnetic waves of a dead person can maintain a brain-like structure in some kind of standing wave. The problem is that this is a reach for science where nothing similar has been observed or even theorized.
It might also be that the electromagnetic remnants of our lives might remain organized in some way as they travel from the earth at the speed of light. These complex wave fronts might interact with nebulas or stars to create standing waves where consciousness exists in high-energy plasma. This is far-fetched, but sciencefictional. I seem to remember a story where astronauts find a region of space inhabited by the ghosts of all those who ever lived and died on earth.
There is a reoccurring science fiction meme where aliens probe the brains of the newly dead, reincarnating humans for nefarious purposes.
Another method for creating an afterlife would be like the Keats character in Hyperion by Dan Simmons. Powerful computers recreated the romantic poet Keats. The new Keats was based on all the information that could be discovered about the original Keats. The character was Keats in every way possible except that the actual memories and personality were an interpolation. No matter how good the reproduction would be by this method, there would be gaps and estimates in the personality and memories. The results, however, were that they created a person very nearly identical to the real Keats.
One of my favorite ideas is that we are all parts of a hugely complex computer game. There are calculations that seem to show that we have a high probability of existing inside a computer simulation. It could be that our universe is nothing more than a very detailed computer program. It is so real that you and I confuse our surroundings with reality. Could reality be as strange as the world we live in?
If we live in a simulation then we might be able to hack our way out of it someday. If we do, we run the risk of being shut down, though. We could cobble together an afterlife if we had some decent programming skills. It may be that the programmer who created the simulation has kindly allowed us a life after death, already. I hope they allocated enough storage for it. That would be a kindness.
Another interesting sciencefictional notion is that the multiverse is infinite. It may be that there an infinite number of universes like ours. The concept would be that in a reality where there are infinite different universes there would be infinite versions of ourselves, each one slightly different. In one of those universes, we would not die. We can only hope that we are living in that one, but if we are not, there is universe just like the one we are in right now where we are identical in every way except that we don't step in front of the bus, develop cancer, or grow old. I hope that's the one I'm in, but if not, I can have the satisfaction that somewhere in some alternate universe, I don't have to worry about dying.