Sorry for the short novel but this topic is fascinating to me.
Okay, so it looks like "existence ex-nihilo" is a phrase I cooked up from "creation ex-nihilo", and the accepted term is more like "first cause", but it explains the problem I have with a purely material universe. Either our entire universe with all its complexity and scale spontaneously exists from nothing - "ex-nihilo", or no first cause - or it has infinite regress, an infinite age, which doesn't fit with what we know of thermodynamics. We would need an infinite source of useful energy to maintain a universe for infinite time.
The pure materialists have all sorts of rebuttals. I've heard of quantum spontaneity as a first cause, but like... for quantum spontaneity to exist, there has to be a substrate of physical laws that cause quantum effects to happen in the first place. That can't be the baseline of existence.
And if they say that cause & effect breaks down at the boundaries of the universe, well, that's just another way of saying that it gives way to a supernatural reality. Because ultimately science is about cause & effect, it is about the laws of nature, so anything that goes outside of that schema is, by definition, supernatural. That's all supernatural means, beyond the natural. You can also talk abut physical laws vs the metaphysical, it's just different words for the same thing.
And science is fundamentally only capable of interrogating the natural, the physical. The analogy I've used to explain this to materialistic atheists is of a simulation. Imagine we exist entirely within a simulation. Well, if we wanted to use the science that exists within this simulation to interrogate the world outside the the computer we're in, we couldn't. You could not design an experiment that would give repeatable results because whatever existed in the physical world beyond the simulation would be entirely unaffected by it. The creators could walk away or change the external environment at any moment, they could turn off the simulation, unplug it, move it to another continent, wait 20 years and plug it back in and we would have no way of even knowing it had happened. They would be outside of our space and time entirely. They could edit out our attempts to understand. The simulation idea is just spirituality with a veneer of sciencey-sounding language. It's functionally no different.
So any evidence of anything beyond the physical is going to necessarily be anecdotal. You can do surveys and such things, but you can't get a systematic data set. It could easily be that non-physical phenomena are shy of direct inspection, who knows.
My partner back when we were both gradually leaving the faith took an online philosophy course from some university, and I sort of took it in over their shoulder. The 101 course started with a discussion about the existence of god, which is the classical way of discussing spirituality. It probably helps that "god" is one syllable whereas "metaphysical reality" is seven. The basic takeaway was, we've been discussing this for thousands of years and nobody has yet come up with a slam-dunk answer either way. This is entry-level stuff in philosophy.
The reddit atheist bros are doing philosophy, but they don't realise it, so they just keep tripping over their own balls. They want to use a "null hypothesis" and shift the "burden of proof" but there is nothing more or less natural or "null" about assuming no first cause as there is about assuming a cause that exists beyond the boundaries of cause and effect. They refuse to learn any philosophy, instead assuming that the tools of science can answer everything, but that in itself is a purely materialist assumption, so it's downstream from philosophy. They are literally begging the question. They're right that science cannot disprove spirituality, but it can't prove it either, regardless of what is real. In my experience it's very hard to get them to see this point.
Their arguments in my experience are always geared towards attacking evangelical christianity, which is actually an easy target. Evangelicals are fucking ridiculous when you strip away their respectability and institutional support. But then when they're done with that target they turn the same weapons on the whole notion of spirituality and it just blows up in their faces. This is why these kinds of atheists are also called "christian atheists". They just don't want to admit that's what they are; it's purely reactionary. Their thought leaders seem to be mainly intellectually lazy grifters who have long since drifted back into an alliance with christianity and started attacking islam instead. Almost like they were always just attacking easy targets and the audience for anti-christian stuff turned out to be smaller than the one for anti-muslim stuff, at least after 9/11.
As for what I personally believe, I'm actually fine with the existence of an afterlife, and with its nonexistence. I found The Good Place ending amazing in this regard. They handled the notion of death so well, and they hit on something fascinating, which is that even if you've seen a thousand afterlives and been alive for billions of Jeremy Bearimy's and seen and done all that you're curious about in the universe you still have no idea what awaits beyond death. Oblivion is not a thing that you can grasp.
So yeah, I've realised that it doesn't matter either way.
