What would you hand me that would be undeniable for anyone to see?
The problem you have is that things in evidence (I mean actual evidence) don't have to be believed in before they can be validated. Just like your example, when I took the ice cube out of the freezer, you could deny it all you like, but anyone watching us would know you were certifiably insane. The same would not be true of people standing around watching you tell us about the undetectable spiritual experience you swear you are having. One is not dependent on someone already being on your "team". Real evidence is its own team.
Science does morph and change, because it retains the humility required to learn. It doesn't confirm any greater truth than what it confirms in fact, not speculation. Those are called "hypotheses" and remain so until the evidence to solidify them takes them to the next realm.
Why do people of different spiritual traditions have throw downs over spiritual revelations if they can be confirmed, tested and validated?
Because they can't, because those terms indicate that data can be shared with anyone and be accepted, not the chosen few that simply "believe".
Perhaps it is best to start with a definition of your terms. You say most people are spiritual. Define how you are using the term.
Who knows? You might have such a gelatinous definition that I'll find it hard to disagree.
Lots more words and still no example of something you accept as proof of something you don't believe in. Why can't you give me an example? All I asked for is one. Surely you can come up with something, since that was your argument?
Spiritual faith is tested all the time. Haven't you heard someone say "my faith was tested?" Those who believe in spiritual nature have all the evidence they need. You can't acknowledge the evidence because you don't believe in spiritual nature. No amount of evidence is ever going to suffice because you reject it. Doesn't matter if you are among about 14% of the human race that doesn't believe in spiritual nature, that never does phase you.
You totally missed my example with the ice. The faucet represents science. Ice represents God. The water which normally flows from a faucet is physical nature. You turn on the faucet and ice doesn't come out, so you conclude that ice must not exist or is not real. I can show you ice from the freezer, but you reject anything that doesn't come from the faucet. The freezer and what comes from it are "anecdotal" in your mind. I can never prove ice exists to you because ice is never going to come out of the faucet, it can't... if it did, it would no longer be ice. I can put the ice in your hand, everyone who believes in the ice can see me do that, and you just smile and say, "that's nice, but it didn't come from the faucet, so I don't believe it is real!" The rest of us just shake our heads. You don't get it, just like you didn't get this analogy.
I don't just "say" most people are spiritual, it's a known
fact. 86% of us worship some spiritual power greater than self and do so regularly. Humans would not do this if there was no benefit to them, if it were a meaningless practice. This has been going on for all of man's existence. Through century after century of jealous kings and tyrants trying to stomp spirituality out of the hearts of man. It can't be done. We refuse to abandon our spiritual connection.
Science NEVER concludes something as fact. Everything in science is theory. There is an important reason for this. Science is the human practice of investigation. Investigation of possibilities. Once something has been concluded as fact, there is no more science to be done, no other possibility exists, science is through...
FAITH begins. You can't practice science on a fact, there is nothing to do. Science has to be able to investigate, ask questions, hypothesis and theorize. It cannot do that with something that has been established as a fact. Even the most clearly indisputable aspects of scientific discovery which we can all universally agree on, remains theory in principle. Even things science establishes as laws.