The only way you know that a person is in front of you and speaking to you is a physical/chemical process in your brain. Why should a natural process kick in? If you've ever done psychedelics you have some awareness of the profound ability of that four pound ball of cells between your ears to create perceptions that seem like reality.

In the absence of EVIDENCE of supernatural realms and the occasional lifting of the veil between us, that ability alone is sufficient to explain what seems like "the transparently obvious";)