The article doesn’t have any definitive answers and doesn’t rule out spiritual possibilities.
“Dr. Ken Ring published a paper in the Journal of Near-Death Studies (Summer, 1993) concerning near-death experiencers who, while out of their bodies, witness real events that occur far away from their dead body. The important aspect to this phenomenon is that these events seen far away are later verified to be true. Experiencers not only witness events from great distances, but they have been documented to hear conversations between people at the same events. Conversations such as these have also verified to be true. An even more fascinating phenomenon occurs when the experiencer actually appears in spirit to someone, usually a loved one, during their NDE and it is verified to be true by the experiencer and the loved one. It is evidence such as this, if scientifically controlled, that can provide absolute scientific proof that consciousness can exist outside of the body. A scientifically controlled NDE that can be repeated which provides such evidence would be the scientific discovery of all time. However, science does not yet have the exact tools to accomplish this. But, science is coming very, very close. This kind of evidence and others provide very strong circumstantial evidence for the survival of consciousness.”
near-death.com/evidence.html