Is spirituality an emergent property?  If an emergent property is dependent upon the joint interactions of existing physiological systems, then, yes, spirituality, like consciousness, is an emergent property.  It is the inevitable product of human complexity. Put another way, complexity breeds complexity
     If this is true, then we must ask another question.  How did the initial simplicity of human systems become a complexity?  Moreover, why did spirituality emerge and not something else?
     It's too easy, of course, to say that it's the work of God, and that, as some would suggest, this is the way God chose to create humans as spiritual beings.  This doesn't really answer the question.  Better to ask about the nature of the forces previously resident in the brain and why they birthed this type of complexity.  Better to wonder why the human brain produced, as it appears to have done for consciousness, spirituality. What was it "thinking"?
     And this takes us into a much larger question.  Why did a material and impersonal brain ever come to consider or generate something exactly its opposite, a personal and immaterial experience?
     Sure, we material beings all have immaterial experiences.  We all birth complexity. But the question remains:  why?  At this point, it's difficult to explain this "why" without assenting to a beginning, however it happened, that is rooted in a personal God. Otherwise, we will keep going further and further back into impersonal materiality until we reach, well, impersonal materiality.  And we're back to square one.
     If spirituality, broadly speaking, is inevitable, and it definitely appears to be, it seems we must admit to the originating fact of its presence.  The rest is up to our physiology.
     Speaking of emergence, if you live in a colder climate, I trust you're enjoying the onset of spring!