How do you define "functional spirituality", and what are those fundamental topics that you feel someone must understand to be considered spiritual? Religion can also become a set of blinders that keep one from discovering or accepting meaningful inspiration and practical advice.
I have no idea what this even means.
The answer to your question is in the round brackets immediately after the phrase "functional spirituality". I don't think that my answer is that hard to fathom.
Then to address that thing that you say you have 'no idea what it means';- that is a practical test that will elucidate on all the aspects that need to be accounted for in my answer to your first question.
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I chose not to produce a laundry list of topics, because that sort of list is easily denied and argued against, because there is no obvious a-priori imperative to have a list of particular subjects to be contended with. I could offer you such a list, but its too easy to have it dragged through the mud of disinterested speculation that choose rather not to investigate deep enough, so instead I formulated the answer in the subjective form of a consistency with one's own intelligence.
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To offer a taste of some of the things on my personal list~
An example of a deep philosophical topic that this question relates to inside my own doctrine of spirituality is this:
(...now this is why I didn't write out these sorts of issues into a list, because they rely on a certain level of jargon in order to access the philosophical issues without being entirely abstract because of verbosity-)
[(this is but only) one fundamental] Question: how does the individual mind reconcile between the external referencing of an objectively stated experience, and his subjective perspective on that same experience, without an irreconcilable dualism (of irreducible un-fungible-ility between internal and externally referenced claims of truth)?
Answer with recourse to religious doctrine: The "Son" (of God- which we are all said to be in the Christian Scripture), is often regarded to be somewhat interchangeable with the phrase "The Word" in Scripture. This philosophical treatment by the Religion offers a very clear understanding of doctrine in Christian Spirituality: The Son, and the Word are alternatives depending on the point of view of the perspective, either (in the case of the Son-) being of the perspective of the spirit's own internal grounding, or (in the case of the Word-) the objectively stated referencing to its own internal grounding.
There are other Scriptural passages that would have to be considered in order to understand the broader depth to this example question, to furnish it with further reaching significance, but that requires to define more jargon:
Spirit= the chosen theme of an intentionally, the purpose imbued by the will, the purpose at the center of the intending to do something... (^I've tried to stating it 3 times in slightly different ways just there).
Also, a lot of further reaching affects of this understanding comes from understanding the planes that make up the lived experience: (famously in Scriptures- heaven and earth (and also an unconscious realm: 'the world'))
ie.
Mat 16:19 And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
^ In this way, the Religion has given me enough grounding to know what I have to account for in my understanding of psychological reality, and how it functions to produce pathological unconsciousness, and the spiritual death in the "false-ego". The Bible doesn't itself contain any life, it commands very specific ways to building a Church that can attain to such advanced understandings;- but this requires sensibilities which are very peculiar to the machinery of worldly authority, and so it is not undertaken or taken seriously by the groups of people who are maybe trying to seek the truth, or perhaps just want to look like they are seeking it.
