Some non-believers in an afterlife, influenced by positivism, have argued that claims of an afterlife are unverifiable and unfalsifiable, and therefore cognitively meaningless. Some have argued that, on the contrary, particular claims concerning the nature of the afterlife are verifiable and falsifiable: all one has to do to verify/falsify them is die. On the other hand, they argue, the belief in the absence of an afterlife can be attacked as vacuous on the grounds that the statement "I cease to exist" is unverifiable, unfalsifiable, and therefore by the same token cognitively meaningless. In particular, the concept of our own non-existence is inconceivable (what experience corresponds to your own non-existence? none.) Schopenhauer in particular argued that the idea of an afterlife or immortal soul is contradicted by the fact that it is impossible to attach sense to such a concept as the soul without reference to characteristics such as consciousness, which depend on such physical entities as the brain. Such concepts he argued, are beyond our reach and noumenal (thus unknowable).
Other philosophical issues about the idea of an afterlife can be expressed in thought experiments. Johnny is shot and ceases existence for five minutes ( allow, for the sake of the thought experiment, regardless of your beliefs, that he does not experience any form of afterlife in this time.) Then, five minutes later Johnny is cloned, an exact replica is made, possessing all of the factual knowledge, beliefs, values, intentional states and emotions etc he had at the time of death. Is this being the same Johnny that was killed? The result of this thought experiment is arguably very important to some religious groups.
Now, imagine that in accordance with the doctrines of some religious groups, that a person X dies and is ressurected after a period of death and essential non-existence (lack of awareness). Is this X the same X that died? The issue at stake is essentially whether identity is continuity over time, or a set of traits, i.e complexes of memory, personality, a soul etc."