Of the things that kept me a Christian, least important to me was the historicity of the Bible, even though, to this day, I still have a high regard for the Bible as a historical document.

The second most important was the evidence of the effect of God in the lives of the people around me at church.

But the most important, beyond anything else, was the subjective experience of "the Spirit". I wasn't pentacostal, but I was all-in as a Christian; It sounds so woo-woo, but I don't know if most people are aware how convincing a truly "spiritual" experience is, even most Christians, since most Christians seem to be cessationist about the most basic interactions with the Spirit (not just healing, prophecy, speaking in tongues, etc.), even if their theology says otherwise. For example, whenever I had a big decision to make or something I was anxious about, I would find a place where nobody could hear me, sing a few hymns, read a few Bible verses picked totally at random, and pray-- not about my decision, just prayer in worship of God-- and without ever actually addressing my issue, within a short time, I almost always had a profound peace about which choice to make, even when that decision went against my insecurities, my rational thought, my will, my perceived abilities, or all of the above. I didn't know or even care the degree to which praying for "stuff" affects the outside world, but I knew prayer affected me and made me a better person.

There are even little "tests" you can contrive out of the Bible to experience "the Spirit". There's a verse, 1 Corinthians 12:3, that says that nobody can say "Jesus is Lord" except by the Spirit. (Obviously, anyone can say the literal words, but to actually mean it is harder.) Anyway, I know some Christians who take this literally, and taught me to pray the words "Jesus is Lord", and when I did, something deep inside always responded, "Amen!". Romans 8:16 could be used the same way, i.e. "I am a child of God". Really, any Bible verse or anything I knew with 100% certainty would elicit the same response. But trying the same experiment with any other phrase would only leave me feeling gross inside.

Anyway, I started to have doubts in the mid 2010s. First was the realization that other people's testimony of their spiritual experiences wasn't terribly reliable. For example, I once went to a prayer meeting while visiting friends in a rural, less educated town, and, while for the most part I had a good time, I was rather culture-shocked by the fast and loose way the Christians there used (and meant) the word "miracle" to describe positive but entirely mundane life events. Like I'm glad your brother-in-law saw an incremental improvement in his cancer this week, but, I mean, the rain falls on the just and unjust alike; it seems more superstitious than spiritual that you credit his improvement entirely on last week's prayer meeting. But whatever, it's a small thing and it doesn't really matter.

But then I noticed a similar trend in the Christians I looked up to. This isn't a spiritual example, but my church was politically mixed, and while I didn't care too much that my friends were supporting this candidate or the other, there was a definite uptick in cognitive dissonance from the 2015 political realignments, leading to people convincing themselves of viewpoints they didn't even remember they disagreed with just last week. The ability to rewrite history en masse with no knowledge it was ever rewritten was something I'd never experienced so viscerally prior to that. (I get that people have a tendency to believe whatever they want to believe, but I'd never seen it at this scale and to people so mentally stable and intelligent.) I finally started to understand how so many secular Bible historians could agree that the early disciples of Jesus genuinely believed they witnessed Christ die and rise again yet completely discount the story as inaccurate. Mass hallucinations don't work that way, I always thought.

Then it happened to me too. Now, I recognize that any impression or feeling or answer to prayer from the Spirit is going to be, in many ways, ambiguous. With the exception of those moments of profound peace, you kinda just get a pretty good idea of what you "heard" from the Spirit and accept that there's always the chance you misunderstood. But it was the former, moments of profound peace, that caused me, for example, to turn down work that would've pulled me away from my congregation at home to another town further away, despite already being out of a job at the time. This was a bad move, financially, and eventually I ran out of money and got evicted. Now, the Bible doesn't make that many concrete, single-variable, testable promises about what's supposed to happen to a Christian walking with God, but one of the one's that's strongly implied is that if you "seek first the kingdom of God", your basic needs will be provided (Matthew 6:31-33). I get that there are going to be exceptions to this, and I'm not trying to imply a prosperity Gospel, but I don't live in a third world country and I wasn't being persecuted and there was no reason to be struggling financially in my position short of irresponsibility. I was genuinely "seeking first the kingdom", and the result was personal failure. And whether or not I've taken the Bible too far to contrive a promise that isn't actually there doesn't really matter, because the Spirit said it was a promise, or so I thought. Clearly, I misunderstood.

The problem is, if I misunderstood the most obvious, unambiguous things that the Spirit told me, nothing is trustworthy.

The other problem is that I had been noticing that it didn't seem like I was spiritually growing as much, despite staying out of sin and following the Bible to the capacity I was able. Christianity clearly had made me a better person from the moment I converted from atheism until several years after, but it seemed like whatever character flaws I still had after five to ten years were just "stuck" in place, and, in fact, this seems to be the normal Christian experience. My pastor mentioned to me a book he had been reading-- I wish I could remember an author or title-- that mentioned that the average Christian is good for about seven years, and then they become a warm body for the rest of their lives. He meant it as an admonishment to continue walking with God, but seeing as I thought I was walking with God, I looked around the church and was horrified to slowly realize that this characterization matched my experience of the Church. It's still the same God; He didn't change. So what changed? Some of the best people I ever knew I knew from church, but they still had rough edges that were never addressed. If anything, the congregation was just getting more cult-like and rigid ("rigid" in a religious way, not in any actual adherence to the Bible) over time.

Eventually, I found myself overwhelmed with doubts. I started running little spiritual experiments. Once, I was taking a shower, and I started doing the "Jesus is Lord" experiment, except that I found that with a little mental gymnastics, I could coax the same response from random objects; like, I could say "shampoo", and something inside would say, "Amen".

After that, the idea that "the Spirit" was all in my head seemed more plausible than the existence of God. So that was basically the end for me.