We might feel very sure that there is no more to reality that the material world in which we live, but we cannot prove that this is the case. Theoretically there could be other realms, other dimensions, as all religious traditions and quantum physics alike maintain. Theoretically, the brain could be as much a receiver as a generator of consciousness and thus might be fine-tuned in altered states to pick up wavelengths that are normally not accessible to us.

...at root, what unites us are our unproven irrational beliefs of one kind or another of non-material dimensions of reality, inhabited by incorporeal beings that interact with us and frame our destiny in mysterious ways

...at root, what unites us are our unproven irrational beliefs of one kind or another in non-material dimensions of reality, inhabited by incorporeal beings that interact with us and frame our destiny in mysterious ways.

It takes courage to throw off unproductive methods and approaches that the majority of scholars in your field have unquestioningly yoked themselves to for decades.