The case for life after death consists in empirical (observable) and nonempirical (theoretical) arguments. The empirical arguments are two: near-death experiences (NDEs) and the resurrection of Jesus. A sufficient body of evidence exists for the view that people have died, left their bodies, had various experiences, and returned to their bodies. Attempts to explain NDEs as natural phenomena fail in those cases where the disembodied person gained knowledge about things miles away (e.g., conversations of family members). One must be cautious about theological interpretations of NDEs, but their reality is well established. Some argue that, even if true, NDEs provide evidence only for temporary existence beyond death. Strictly speaking, this is correct. However, if biological death does not bring the cessation of consciousness, it is hard to see what could do so after death.
Jesus' resurrection is defended in other articles in this Bible. Suffice it to say here that if Jesus rose from the dead, this qualifies Him to speak about life after death because His resurrection provides evidence that He was the Son of God and means that He returned from the afterlife and told us about it.
The nonempirical arguments divide into theistic-dependent and theistic-independent ones. The former assume the existence of God and from that fact argue for immortality. If God is who He says He is, the case is proven beyond reasonable doubt. Three such theistic-dependent arguments are especially important.
The first is two-pronged and argues from the image and love of God. Given that humans have tremendous value as image bearers and God is a preserver of tremendously high value, then God is a preserver of persons. Moreover, given that God loves His image bearers and has a project of bringing them to full maturity and fellowship with Him, God will sustain humans to continue this love affair and His important project on their behalf.
The second argument, based on divine justice, asserts that in this life goods and evils are not evenly distributed. A just God must balance the scales in another life, and an afterlife is thus required.
Finally, there is the argument from biblical revelation. It can be established that the Bible is the truthful Word of God, and it affirms life after death. For this to be an argument, rational considerations must be marshaled on behalf of the Bible's divine status.
Two nontheistic dependent arguments exist for immortality. The first is a three part argument from desire: (1) The desire for life after death is a natural desire. (2) Every natural desire corresponds to some real state of affairs that can fulfill it. (3) Therefore, the desire for life after death corresponds to some real state of affairs-namely life after death-that fulfills it.
Critics claim that the desire for immortality is nothing but an expression of ethical egoism. People do not universally desire it, and even when they do, it is a learned, not a natural, desire. Further, even if it is a natural desire, sometimes such desires are frustrated. Thus the desire argument is not necessarily a strong argument, but nonetheless it does have some merit.
The second argument claims that consciousness and the self are immaterial, not physical, and this supports belief in life after death in two ways: (1) It makes disembodied existence and personal identity in the afterlife intelligible. (2) It provides evidence for the existence of God. This, in turn, provides grounds for reintroducing the theistic-dependent arguments for life after death.
The argument for consciousness being nonphysical involves the claim that once one gets an accurate description of consciousness-sensations, emotions, thoughts, beliefs - it becomes clear that it is not physical. Conscious states are characterized by their inner, private, qualitative feel made known by introspection. Since physical states lack these features, consciousness is not physical.
The case for an immaterial self is rooted in the claim that in first-person introspection we are aware of our own egos as immaterial centers of consciousness. This awareness grounds intuitions that when one has an arm cut off, has a portion of one's brain removed, or gains or loses memories and personality traits, one does not become a partial person or a different person altogether.
While these two arguments provide some grounds for belief in an afterlife, they are far from conclusive. At the end of the day, the justification of belief in life after death is largely theistic dependent.
Extracted from the Apologetics Study Bible.