Tether Theory
First, the mind and body are separate things. The mind cannot be isolated as a part of the body, it exists metaphysically. The mind and consciousness is not just a set of rules and ifs that create awareness, otherwise something like a computer or a calculator or a board game could become conscious if given enough rules, and simulated consciousness is not consciousness. Consciousness is something inherently anti-scientific. It cannot be observed, measured, or studied in any way, because science can only deal with the physical and material.
Then, if the mind is fully immaterial, and the body is fully material, how do they interact? A tether, a link, something connecting them. When death is achieved, the tether is severed. The body is raised from being a set of chemicals and molecules, raised into motion and life, raised into something more than being purely physical, by its link to the mind. The mind is lowered from being something purely immaterial and metaphysical to something able to control and interact with the world, perceive the world, and so on by the tether to the body. The tether blends the physical and metaphysical together for the body and mind.
Through this, the mind becomes more physical and the body becomes more metaphysical. As stated before, the tether can be severed, resulting in death. The body becomes purely physical, a pile of decomposing meat. The mind becomes purely metaphysical, drifting completely to the spiritual realm. But is this a simple binary system? Either the tether exists or doesn't exist? Are there degrees? Yes.
The tether can absolutely be modified, weakened, and so on. When the tether is modified or weakened, the body becomes more material, while the mind -- our experience and perception and so on -- becomes more immaterial. As a first example, hypnosis. When someone is hypnotized, great achievments can be accomplished. Not trivial things like breaking addictions, but true marvels. I have seen people and interviewed people whose perceptions of themselves, what they literally see in the mirror, completely and utterly changes to something nonhuman. And then as a result, their physical behaviors modify in accordance, walking digitigrade rather than plantigrade as an example. It horrified me.
But then there are other results other than simply modifying perceptions or breaking addictions. When people repeatedly experience hypnotic trances, where their minds are exposed and laid bare for the hypnotist, strange things begin to happen. Their mind's defenses become battered and worn. Soon enough, they can collapse. This leads to the tether itself weakening, the mind begins to slip more into the metaphysical and the body begins to slip more into the physical. The two parts of the person begin to drift to their original corresponding states.
What do I mean by this? I have seen people who are repeatedly hypnotized and have their tethers weakened. They begin to hear other voices in their heads. They begin to lose control of their own bodies, being piloted by other beings, a prisoner in their own mind while a wholly separate mind takes control. Not at a hypnotist's instruction, but completely separate and apart from the prior trances. And if it gets bad enough, the spirits and such will manifest directly. They are purely metaphysical beings, so they cannot affect the physical world or body, but can affect the metaphysical sensory perceptions. The mind drifting to the metaphysical leads to the mind being able to perceive things it normally would not be able to -- not through the body's physical eyes, but with the metaphysical senses that correspond to the physical. The body has eyes for the physical, the mind has eyes for the metaphysical. When the tether is weakened, these metaphysical senses become unlocked.
This is not some super-power. It is a dangerous sign. Manifestations and appearances, voices in the head, seeing people that aren't there. But the people who experienced these effects write them off as harmless, exciting. Many of them point to the oriental mystic traditions of things like Tulpae. Nonsense. These entities must necessarily be demonic in nature, and simply disguise themselves as allies. In exchange, partial or occasional control of the body, influence of the person, and so on. Nothing good.
Perhaps with enough hypnosis and mental-battering, the tether can be completely snapped. It has happened before, people dying from hypnosis. Twice in history, at least. These cases are perhaps not exactly what is suggested, with them likely being due to stresses from the hypnotist's requests, not from the simple act of repeated trances. However, this is still interesting. A death at the mere result of suggestion. A physical death achieved by words. Curious.
What other ways can the tether be weakened, or modified? For one, some people have weaker tethers than others. They can perceive things others can't. I knew a man who was schizophrenic. He would hear footsteps outside his room. He would hide under his bed in fear, seeing living amalgamations of flesh and organ in his room, or skittering half-human creatures roaming the hallways. It terrified him. These creatures are not simply hallucinations. They are physically present, they are spiritual and metaphysical beings, demonic in nature. They cannot interact with his body, but they can interact with his mind, his metaphysical senses and such.
Or for example, certain drugs. Some drugs like psychadelics are perhaps in this category, but I mean drugs that lead to strange hallucinations. A popular and well-known example is Benadryl. Take enough, and you will see spirits. Why? Because this weakens the tether. No wonder people die if they take too many, they overstretch their tether and it snaps, killing them. People see things like the hat-man, recurring figures across nations, tongues, and cultures. Why? Because the hat-man is real, and is a metaphysical entity. Only by weakening the tether can the mind slip into the metaphysical perceptions and see these entities.
Then take also for example, when people approach death. Christopher Knight one day was near death, hypothermic. He saw death, a woman, sitting near him, waiting. This was not a hallucination. Other people while near hypothermic death do perceive metaphysical entities watching and observing. So many people while near death claim to see beings, spirits and angels, assisting or observing them. These people are not hallucinating. Their tethers are simply weakened by their near-death state, and so the metaphysical becomes plainly observable.
Is there any way to restore the tether, to strengthen it? To recover a weakened tether from injury? Possibly. I truly do not know. I figure that if certain drugs like Benadryl can weaken the tether, then there surely is some drug that can restore it. Perhaps some types of antipsychotics. But like Benadryl, these are only temporary fixes, not permanent ones. Permanent fixes would likely require some more metaphysical methods, rather than material ones like drugs. Drugs affect the body's side of the tether, perhaps something like hypnosis or prayer could affect the mind's side of the tether, which may prove more fruitful. After all, the mind does not metabolize like the body does.
There are many, many examples of tethers being weakened, leading to people's minds drifting to the metaphysical. They perceive spirits and manifestations that are truly there immaterially, and various complications can arise. A totally broken tether results in death. Restoring the tether, while there is no known method, would necessarily result in resurrection.