Indeed, the militant a-Theist pretends to Gnosticism; becomes equally, the bastard son of Certainty.

As to the 'spiritual' -- undemonstrable as any such an experience would be, beyond the experiencer's jelloware: I note that most non-fulminating assessments of corporate theology (ie. of all organized groups with fav manuals, hierarchy, garb and rituals) - tend to point out that there are many churchly habits that militate against ever experiencing the spiritual - in favor of the adsorption of the Authoritative.

Allegiance to the org. substitutes for experience of the [__].
Only homo-sap could contrive a Living Oxymoron!

No wonder.. it is so rare when anything potentially useful ever gets said, in the usual clashes within the World of Opposites '..as ignorant armies clash by night.'

(At least the ~'agnostic' never pretends to Certainty: a concept which may be prominent on the epitaph of the radioactive ruins, if a dying stonemason has the energy to chisel anything much, after RIP.)