Quite often on this blog we've talked about the transmission hypothesis, which can be expressed in various forms, but which always boils down to the idea that the brain is a medium by which consciousness interacts with the physical world. When the brain dies, consciousness continues, though it is no longer physically embodied. This is one basic answer to the question of how personality can survive the death of the body.
One of the most common objections to this idea is that the mind can suffer severe impairment as a result of neurological damage or other physical problems, so that, even if the mind does survive death, it will survive only in a grossly impaired form. On the other hand, it is argued, if the postmortem mind is free of all physical impairments, then it bears little or no resemblance to the embodied mind and therefore amounts to a whole new mind. In this case, there is no continuity of consciousness between the premortem and postmortem mind, and so there is no individual survival.
There are two ways to counter this argument. The first is to forego philosophizing and simply look at the empirical evidence that convinced us (or some of us) of life after death in the first place. To me, the best evidence is found in the trance mediumship of women like Leonora Piper, Gladys Osborne Leonard, and Eileen Garrett, all of whom were studied intensively for decades by serious investigators, who left behind reams of stenographic records of hundreds of sittings. Some of the material that came through these mediums was incorrect, and a great deal of it was nonsense ("bosh," William James called it), but all serious researchers were eventually led to conclude that a significant minority of the communications contained information that the mediums could not have obtained by any normal means. These researchers were divided between the hypothesis of postmortem survival and the hypothesis of super-ESP.
Personally, I think the super-ESP idea has little merit; for a detailed discussion, see Chris Carter's Science and the Afterlife Experience. This leaves us with postmortem survival. And the hypothesis of personal survival is further supported by near-death experiences, out-of-body experiences, apparitions, deathbed visions, terminal lucidity, past-life recall, and other cases.
What all of these instances have in common is an insistence on continuity of consciousness. The deceased, speaking through mediums, tell us quite plainly that they are still the same individuals that they were when physically alive. This point is repeated over and over, almost ad nauseam. We are told that the transition between life and the afterlife can be so seamless that the person is unaware of having died. In other cases, the transition is more difficult, but even then the discarnate communicator invariably tells us that he has the same sense of self that he had when living on earth.
People who have had near-death experiences also report no disruption in the continuity of their consciousness. However much their consciousness may have been expanded or otherwise affected, they retain the sense that the entire episode happened to the old familiar I of personal experience.
Since this is what all the evidence tells us, there is really no reason to doubt it merely on philosophical grounds. It would make more sense to rethink our philosophical arguments than to discard empirical evidence.
But there's another way of tackling the problem — namely, to sketch out a philosophical position consistent with the empirical evidence. For what follows, I'm indebted to the contributions of several commenters on this blog, particularly Matt Rouge, who first brought up the concept of the I-thought and its entanglement with an informational matrix.
To get into this, we first need to think a little about what consciousness is.
Consciousness implies both a subject and an object. This much is obvious, but most people have a mistaken idea of what the subject is. I think it is this mistake that makes it hard to appreciate the force of the transmission hypothesis.
To describe what the subject is, let's first detail what it is not. The objects of consciousness include sensory input, mental imagery, logical reasoning processes, memories, imagination, feelings, and thoughts. Yes, even thoughts are objects, not subjects, of consciousness. What, then, is the subject? It is pure awareness – nothing more and nothing less.
Pure awareness, when linked to a specific set of objects, is known in some traditions as the I-thought. It is described this way in The Advaita Worldview: God, World, and Humanity, by Anantanand Rambachan:
The I-thought is centered on an awareness that is permanently present, being timeless and self-revealing. Its content and nature are nothing but awareness, without which it has no existence or reality. ... When the I-thought, whose nature is limitless awareness [ ] is subject to ignorance, it identifies itself with the characteristics of the body, senses, and mind in notions such as, "I am short," "I am blind," or "I am unhappy." Liberation from ignorance occurs when the I-thought [ ] comes to understand its nature as limitless awareness. … A requisite of such knowledge is a calm and translucent mind in which the I-thought is able to understand itself as nonobjectifiable, illuminating awareness, distinguishable from the body, senses, and mind, relating to all of these as subject to object, and as identical with brahman, the non-dual ground of all reality. ...
All thoughts originate from and can be reduced or resolved back to the I-thought. The I-thought, on the other hand, can be traced back to its source in awareness, without which it ceases to be. Awareness, however, cannot be resolved or reduced it to anything else. It simply is.
The I-thought persists throughout life, as well as during and after the transition to the afterlife. It thus accounts for the continuity of consciousness and for the often-reported insistence that the deceased "I" is the same as the physically embodied "I."
When we talk about an embodied consciousness – that is, the consciousness of a person living on earth – we're talking about an evolving dynamic process that involves all the objects of consciousness I listed above, and the I-thought, and the neurological and biological structures of the living organism. When we talk about a disembodied consciousness – the consciousness of a discarnate person – we're talking about an evolving dynamic process that involves all the objects of consciousness and the I-thought, but not the physical structures of the living organism. The absence of those physical structures is the key difference.
No one disputes that neurological damage and other physical problems can impair consciousness while it is embodied. The impairment occurs not because of any change in the pure awareness at the root of the I-thought but because the range of objects of consciousness is reduced. It may not be possible to recall memories, focus on logical reasoning, or formulate coherent thoughts. Again, all of these are objects, not the subject, of consciousness. Pure awareness remains uncorrupted and unimpaired, but the set of objects it can illuminate is narrowed, and the I-thought mistakenly accepts this narrowing as permanent. Upon passing over to the next life, the physical impairments are removed, and the full variety of objects is again available.
Now, for this to make sense, two things must be true. First, the objects of consciousness, even if temporarily lost while consciousness is embodied, cannot be permanently lost. If memories, thoughts, logical reasoning, and so forth are irretrievably lost, then even the transition to a discarnate state would not allow the I-thought to recover them. So there must be some way in which the objects of consciousness are preserved – whether we call it the Akashic records or whether we simply maintain that information, once brought into existence, cannot be destroyed.
Second, we must assume that there is a close relationship between one's awareness and the particular set of objects on which it has focused. Otherwise awareness, once liberated from its physical trappings, might focus on any and all objects of any consciousness that has ever been. In this case there would be no survival of the individual personality, but only a kind of universal mind that is aware of everything at once. While this idea might be philosophically appealing and it is found in some spiritual traditions, it's contradicted by the apparently reliable testimony of deceased persons speaking through mediums, as well as the testimony of people who've had near-death experiences, etc. And in any case, the very concept of the I-thought expressly serves to cover this relationship. The I-thought is pure awareness connected to a particular set of thoughts and memories — individuated and egoic, not universal and identityless. It is an I-thought, not a We-thought.
Given an "entanglement" between the I-thought and the constellation of objects on which it has focused, the I-thought, once free of physical limits, will naturally focus on the one particular set of objects – memories, thoughts, feelings, etc. – that, added together, constitute a "personality." After all, what we call personality is only the intersection of the I-thought with a characteristic set of objects – distinctive memories, personal thoughts and feelings, recognizable habits of mind. This is how we can say that the personality survives death, even if the personality has been grossly attenuated or deformed by dementia, mental illness, and other impairments. It is also how we can say that in cases of terminal lucidity, the dying person abruptly recovers his or her personality ("she was herself again").
An analogy might make this whole thing a little clearer. Imagine a person who is able to see only through a narrow horizontal slit in a blindfold. His vision is restricted to a hazy line, and he thinks of himself as nearly sightless. At a certain point, the blindfold is removed, and after a short period of disorientation and adjustment, he is able to see a much wider range of objects. In this case the person's eyesight corresponds to pure awareness, his self-identification as "nearly sightless" corresponds to the I-thought, and the slitted blindfold corresponds to physical limitations and impairments. The person's capacity for vision actually remains unchanged throughout, but the objects of his vision are restricted at first and relatively unrestricted later, and the I-thought (in its ignorance) mistakes this temporary limitation for a permanent condition.
The bottom line is that the skeptical objection to the transmission hypothesis is flawed in two respects. First, it's inconsistent with the empirical evidence. (Naturally, skeptics will dispute or dismiss this very evidence, but that's a separate issue.) Second, it depends on an understanding of consciousness that confuses subject and object. It assumes that thoughts and memories and reasoning processes are the same thing as awareness, when in fact all of these are objects of awareness in the particular form of the I-thought.
If we look at consciousness as an I-thought entangled with an information matrix in an evolving system that is subject to temporary limitations and impairments, but in which no data are ever permanently lost, the skeptical objection simply becomes irrelevant.