However, in my view, the coherency of belief in life after death hinges on personal identity, which is understood by Stephen T Davis first and foremost to be a metaphysical problem, questioning what criteria should be used for identifying and re-identifying persons. There are two apparent ‘solutions’ to the problem of personal identity. The ‘memory criterion’ is the theory that people are different or identical due to the mind i.e. the personality and memories, and that the memory criterion is sufficient by itself to establish personal identity. The ‘bodily criterion’ maintains that people are recognisable purely by their physical characteristics. In relation to life after death, believers in immortality and reincarnation must accept the theory of ‘memory criterion’, and maintain the only way someone can survive death is if there is mental continuity with their former self, i.e. they have the same memories, aims and personality. On the other hand, believers in resurrection can appeal to both approaches. A person can survive death just by showing some indication of physical continuity with a person who passed before, and it does not matter whether or not there is an additional indication of mental continuity.
However, according to Peter Geach, traditional platonic dualists and believers in reincarnation must accept that personal identity is not due to the memory criterion and those differences of memories or of aims can not comprise the difference between two disembodied minds or spirits. This type of spirit feels no pain, has no thoughts and therefore is not physical and has no mind or brain. It is entirely dehumanized. In its disembodied state, only a remnant of a given person survives, just enough to preserve some sort of physical or mental continuity, but not enough to constitute life after death on the basis of memory criterion or to differentiate between it, and that of another. Effectively, individuality does not survive, and the existence of a disembodied soul would not see the survival of someone. The solution? To look to the future. The soul retains the capacity for a reunion with a physical counterpart with whom it can reform a person identifiable as one who went before, with the same memories and aims previously lacking in the soul’s isolated state. According to Peter Geach, only upon this event can we individuate between disembodied human souls and truthfully and coherently advocate life after death. Yet this still leaves the problem of material continuity; must the material conditions of identity be fulfilled for life after death to be coherent? Must some physical indicator of a given person be retained in life after death for them to be recognisable? If souls differ by being related to different physical states, then it is the difference of matter that partly gives them their identities, and therefore, some essence of this should be kept to ensure continuity. Mental continuity alone is not sufficient; consequently some material continuity is needed, though this need not be material identity. To illustrate this, a baby grows into an old man- we cannot identify the old man as the baby who went before, however it is evident that they have some sort of material connection. Therefore some sort of resurrection is necessary for life after death to be coherent, even if it is not the traditional perception of a human corpse arising from its cold grave. If someone’s soul does not unite with its body and come to life by ‘resurrection’, then only a mental remnant of him survives death, and he does not live. This belief is inline with that of the traditional Christian one. Resurrection is central to the system; it acts as a guarantee that all Christians will be resurrected, and is represented in the depiction of the ‘firstfruits’ in 1 Corinthians 15:3. Whilst the present body is perishable, weak and dishonourable, the resurrected body is glorious, powerful and immortal.
Therefore, to conclude, I would agree with the given contention that belief in life after death is only coherent if we believe in resurrection, despite the problem at first appearing to be a subjective matter. Believers in resurrection can appeal to every solution where the mind-body problem and the problem of personal identity are concerned, and as argued by Peter Geach, even dualists/ believers in reincarnation must return to resurrection to coherently justify life after death. Consequently, in my view, only the possibility of resurrection provides any hope for life after death,
