It’s a fool’s errand to convince a gear-head of the existence of the spiritual realm.
A gear-head? That is new. Here is a very short essay of the question.
The first problem with this “spiritual realm” is its definition. A
non-physical existence, which is nevertheless
physically active. Now there are many entities which are non-physical: ideas, concepts, theories, theorems (they are not the same), stories, tales, and many others. These all exist as non-physical entities, even though they are put into physically recognizable form for the purposes of discussion and description. (Words, of course).
However, NONE of these are
physically active. The
concept of “water” is not “wet”, and cannot be used for boiling eggs. Concepts are mental constructs, physically inactive. (Though one can act on them, but that is not the same.)
Offering indirect evidence of the sensible effects for with no material cause exists only elicits the “brute fact” or “emerging property” ejaculation followed by the usual knee-jerk retort “god of the gaps - just give science more time”.
The problem is with the offered “non-material” cause. First of all, how can a non-material entity interact with the physical world? The offered: “Let there be light, and there was light” is simply “magic”. And of course that WOULD be a physical demonstration. The words: uttered “let there be light…” would be a physical act - since our 5 senses can only perceive a physical signal.
So an alleged
non-physical causative agent (from now on:
NPCA) could easily demonstrate its existence and power to us, if it existed and would be inclined to give the demonstration. Moreover, some of these alleged NPCA-s (gods, angels, demons)
allegedly can be influenced by some of our physical activities - namely prayers, supplications, invocations, evocations, OUIJA boards… - and other physical means.
Your suggested “brute facts” never even get into the picture.
But none of these physical activities “work”, in the sense of a “vending-machine” - you drop in a coin and some predetermined result will follow. They don’t - most of the time. However when there seem to be a causative relationship - you pray for a better job, and in a few months you are offered a better job. And in these cases (once in a blue moon) the supplicant proudly proclaims that the “prayer
worked”. The zillions of unsatisfactory outcomes of other prayers are simply swept under the rug. (The word is intellectual dishonesty!)
So there comes the usual cop-out: “you cannot demand God to do your bidding”. Why not? You do it all the time, when issuing a supplicative prayer (not to be confused by a meditative prayer). Sometimes the alleged positive outcome is used to canonize a brand new “saint” - JPII comes to mind.
So get off your high horse and put the blame squarely where it is. You have no
direct physical evidence for the “spiritual” (even though it would be possible), and none of your offered
indirect evidences “work” - in the sense of allowing to make a prediction and expect a reliable result.