They are the result of an infinite and ever expanding cosmos; absolutely no magic thinking or beliefs are required. I don't need to pretend that magic exists just because processes are complex.
What I'm getting at is the difference between subjective experience ("chills") and any theory describing it. ("Qualia", "no amount of simulating water will make anything wet", etc.)
Although personally I prefer scientific theories to describe reality (they are still the best/most useful), our experience is never "based" on theories.
I don't really have to interrogate why the term "spiritual" has absolutely no meaning wrt the genetic underpinnings of the effects discussed in the study. The study was scientific. It isn't complicated.
Although personally I prefer scientific theories to describe reality (they are still the best/most useful), our experience is never "based" on theories.