Sometimes certain people—they may be called “mediums,” “psychics,” “sensitives,” or (a more recent term) “channels”—transmit what are purported to be messages from departed souls. The medium may speak in trance, or his or her hand may produce writing automatically. This is a field in which parapsychologists have done extensive investigation. It’s a problematic field. Frauds abound.
Much of the material transmitted tends to be stereotypical. The wisdom and insights dispensed by “departed spirits” often consist of a tired litany of new-age platitudes. For discriminating minds, this doesn’t create a lot of confidence.
Most material generated by mediums or channels is unfalsifiable—there’s nothing specific enough to either prove or disprove.
Even when material is specific and impressive and fraud seems ruled out, explanations other than communication with departed souls are available, and almost always more likely.
This doesn’t mean that all mediumistic communication or channeling can be dismissed as worthless. Some carefully investigated cases do seem to hold up under scrutiny and show evidence for possible survival of bodily death. But those cases are rare.
And even if there were genuine communication with a departed spirit, this wouldn’t in itself prove reincarnation. The spirit might presumably be communicating from heaven, from hell, or from some sort of limbo, without any “succession of births.” For that matter, even if a “departed soul” tells us there’s reincarnation, how do we know he’s telling the truth? When people here in this world can be such liars, why not people “there”?