Not really quite sure where you are going with your questions, so I apologize if what follows might seem patronizing. I don't really know what "spiritual" means when religious people use that term. I usually take it to mean - "a feeling good and inspired" type of feeling/emotion. I guess being able to trace and observe the specific neuro-networks that create that emotion could be considered evidence, but that isn't what we mean here. The subject here is the non-natural soul/spirit concept from duality - is it real or not? It is a concept that is currently not supported by any known evidence. Many ideas in science begin with a speculation or concept where there is no initial appearance of evidence for support. An attempt is made to find evidence to support the ideas, and if none is found the idea is abandoned or the search continues, potentially indefinitely. The soul concept can be similarly treated. My last point was about attempting to show that a soul is no longer a viable offering. The idea originated in times of significant ignorance about how the brain functioned - just how could something physical generate such apparently subjective things as thoughts and emotions? With neuro-science comes very clear insights as to how these things are generated in the physical world. Given that we now know the brain provides such things as memory, identity, cognitive abilities, and emotions, all of which were traditionally considered the role of the soul, what then does a soul contribute? It would seem nothing. So what I was trying to say was that looking for evidence to support a soul concept is effectively futile since it is a concept that provides no attributes. Now I know some religionists will claim that the soul is some type of lifeforce and is essential - but that is another whole debate. Just feels like a reluctance to let go of thousands of years of assumption that a soul is real.