This brief and simplified discernment is to elaborate on nature of being ontology beyond known physical world:
If the subtle body-mind of the many sentient composite body-mind system does not exist, then the implications would be:
1.0 At best, there epistemology but no ontology or no existence after physical death. In other words, just stream of consciousness or information during known physical life..
2.0 From 1.0, at best, would be epistemology of a greater epistemology. And greater ontology or an epistemology of another ontology such as sum of parts of greater part(s) of the whole (i.e. a type of existence is necessary to facilitate and sustain life and existence or both epistemology and ontology).
However, implications 1.0-2.0 contradict:
1.0 The human experience throughout the millenniums such as of subtle body-mind, OBE, NDE, and spiritual realms and worlds. If there is no nature of being ontology beyond the known physical world, these experience would never be possible.
2.0 Contradict nature wholeness process and mechanism of being and becoming or wholeness process of evolution and emergence. Another way of saying is evolution and emergence require both epistemology and ontology. And therefore, nature of being ontology beyond the known physical world implied both epistemology and ontology or existence of subtle body-mind rather than just a stream of consciousness.
Both the implications and theirs rebuttals mentioned validate beyond any reason of doubt the existence of subtle body-mind potentialities of possibilities as parts of the many sentient composite body-mind (just the logical and rational or reason is enough. The experience would just further strengthen and complement as empirical data). In other words, the physical body cannot evolve beyond the biologic and known physical world (i.e. require immaterial or beyond known physical world form=formless) . However, the subtle body-mind could or for which reason the existence of the subtle body-mind.
Scientists start to explore. An example of an exploration in progress:
The scientific community is encouraged and urged to explore. And advance the scientific quest of the essence, nature, and ground of being. And nature..
Epistemology of Life and Ontology of Existence Foundation and Institute