If one is to be said to have survived bodily death that one must have maintained the identity of his person after his physical body has expired and begun to decay. The real existence of identity and personhood cannot be assumed and instead must be proved in order to speak with any measure of certainty about survival of bodily death.
There are two prominent theories regarding personhood. First, the Ego Theory, claims that personhood is to be defined as a single principle which organizes and unites a series of sensations, emotions, and thoughts (Parfit). The second is called the Bundle Theory, which claims that the person is simply a bundle sensations and a series of mental states, tied together as if in a bundle or package (Parfit). In its truest sense, Bundle Theory is an argument against personhood. It instead makes the claim that there is no self (Parfit) For the Bundle Theory the person may exactly equal the physical human body. For the Ego theorist it may be something which is the composite of the body and a non-bodily principle called a mind or soul, or it may entirely consist in the mind or soul, excluding the bodily portion from personhood.
Identity is established when one thing can be said to hold continuity with another, such that the chain of causes and effects has been maintained between the two without interruption. If an object or person were to go out of existence for even the minutest amount of time or if it were undergo some sort of essential change, it could no longer be said to maintain identity. Even if it were as Aristotle claimed, that the body was to have been reconstructed in the same form by the same creator out of the same material, it would only be a duplicate because the original act is not what caused it, but a second act by the same creator (Van Inwagen).
In order for the person to be able to survive bodily death, it cannot be equal to or dependent on the body. If personhood was dependent on the body, then the person would obviously expire with the expiration of the body. If the person is not dependent on the body it cannot include any physical sensations, or any emotions or thoughts which have psycho-physical explanations. If this is the case, however, it becomes extremely difficult to pin down exactly what a person is. Devoid of body, emotion, and thought, the person seems to lack personality. The only viable option which still seems available to the person is that it exists as some kind of animating principle. Yet what happens to an animating principle once it ceases to animate? If it continues to exist, it cannot be said to exist in any way which is individual. Lacking a body it would be boundless and immaterial; incapable of sensory experience. It could not be able to exist anywhere and could not interact with any other thing, yet it would be impossible to distinguish it from any other thing as it has no physical characteristics.
The concept of death seems to preclude the continuance of identity after death unless the essential nature of the object was not ended or affected by death. It is for this reason that in order to survive bodily death the person cannot be dependent on the body. It is physically impossible for a material body to undergo death without a complete change, and this complete change ends any possibility of the continuance of identity. Even so, it is not much easier to imagine an immaterial soul maintaining identity through death, as once separated from the ability to sense and feel the resulting principle would hardly be the essential equivalent of the person as they existed prior to bodily death.
The metaphysical theory that a person continues to survive after bodily death leaves the philosophical thinker with a very few options. It is possible that the person is completely independent of the body. In this case upon bodily death the soul-person leaves the body and is not significantly affected by it. This theory brings up significant problems about the interaction between body and soul. If the soul does not require the body, why is it ever associated with the body to begin with? How does the soul interact with the body, in this regard?
It could also be possible that the body is somehow dependent upon the soul, or exists as a sort of illusion. In this case soul continues upon death, only expressing itself in some other manner or in another world and leaving the old body to decay like a shed snakeskin. This seems like a highly conceivable answer, allowing for the necessity of a both a body and a soul, and yet allowing the soul to survive bodily death. If this is the case, however, it does not answer the above criticism regarding the interrelationship of body and soul.
Thirdly, it is possible that through some kind of divine providence the body does not truly die but is moved to a different world, as is suggested by Peter Van Inwagen (Van Inwagen).The difficulty with this last conclusion, however, is that it does not represent actual experience. Instead it requires a denial of what its observable through the senses. Thus, while all three are possible speculative theories, but can never be accepted as fact.
This leaves only one argument which adheres to both observation and reason. There can in fact be no possible survival of bodily death. If one accepts this conclusion, there is no longer any need to theorize regarding a metaphysical soul. It is unnecessary unless one desires to argue for the survival of bodily death. Likewise the assertion of personal self and identity are unnecessary. There need not be any unifying or organizing principle beyond the physical construct of the brain. Since there is no unified soul, there is nothing within which to search for continuity. Identity is equivalent to physical identity; as long as the body continues to grow organically, everything that can be called the person will continue to grow. Once the body begins to decay, the person decays until finally it passes out of existence or into the existence of some other subject.
In conclusion, one is forced to accept the fact that there can be no evidence for the theory of a unified person which maintains its identity through bodily death. With modern advancement of physical and psychological sciences, material explanations for the beliefs and behaviors of philosophers of the past are becoming outdated. The only solution as to personhood which can be coherently held in light of human experience is a entirely material view which allows for the possibility of existence without self or identity.
Sources Cited: Parfit, Derek. “Divided Minds and the Nature of Persons”. Van Inwagen, Peter. “The Possibility of Resurrection”.