In order to avoid the appearance of patronizing your spiritual loved one it is important to have a metaphor whose applicability you actually subscribe to. This can create additional problems as your understanding of the metaphor can be far greater than a spiritualist’s understanding of their own belief.
Many spiritualists maintain that a major characteristic of the focus of their faith is its intrinsic unknowability. They will sometimes try and use metaphors to explain this. The metaphor of the blind men and the elephant is popular. Thus you might find yourself describing metaphors to accommodate a spiritualist loved one’s belief system that they only understand through the use of metaphors.
The greatest thing by far is to be a master of metaphor. It is the one thing that cannot be learned from others; it is also a sign of genius, since a good metaphor implies an eye for resemblance.
-Aristotle, De Poetica, 322 B.C.
The reason one wants to accommodate the spiritualist loved one’s belief as a metaphor is that explaining the substance of a theology as a metaphor can be literally true. I can view Gaia as a metaphor for the interaction of ecosystems to create a planet wide interconnected web with diverse actions that are easily anthropomorphized. I can view chi as a heuristic for impressive neural activities, and I have done so in this very blog.
The Abrahamic gods are more difficult; especially when some well-meaning relative is holding onto your arm while exclaiming that he has personally spoken with Jesus who said to him in English that you would come unto him in repentance and be saved. I once offered to get an evangelical family member a cup of coffee when they added that they would not rest until they saw me on my knees before the lord.
It is hard in the confrontationally proselytizing cases to state that the belief is some metaphor for an actual complex physical reality, and that it might be useful as such. In such cases I want to use the word “symptom”, as in: “your belief in an invisible god that talks directly to you is a symptom of your psychiatric malady”.
Please remember that the winter holidays are a time of accommodation and joy. Avoid the use of the word “symptom” accept in cases of food poisoning, and then be careful not to single out Aunt Bee’s turkey as the causative agent of those symptoms.
When I am both thinking clearly and confronted by a stubbornly literal spiritualist I punt.
“I can understand and believe many spiritual concepts when I view them as metaphors”
If theirs is to nonsensical to be understood after concentrated ninja-like metaphor skills do not volunteer this information.
“Metaphors are such an important way for people to both understand, and communicate their understanding, of the world.”
At this point, if you can provide compelling examples of metaphors you have effectively changed the subject. The problem is that really good metaphors are hard to come by. You can use some dusty old metaphor you read in some book, but the best way to get a good metaphor is to hunt them down yourself.