Why do you assume c. 30 AD was around when Christianity started?

As it happens, I wrote a whole article on that:
How Do We Know the Apostle Paul Wrote His Epistles in the 50s A.D.?

But I think you will benefit on the methodological issues there that I discuss in Can We Doubt Paul Existed? (not directly on point but you’ll see the relevance when you’re in there).

But why would that be necessary for someone outside that fold?

Which question evokes me to answer your first question taking it a different way than you may have intended:

I explain in Historicity why I assume a lot of mainstream stuff there: methodologically, to argue a fortiori. Otherwise if you bog a thesis down with a hundred deviations from the consensus you will fail to persuade, both rationally and psychologically. Every “maybe it’s something else” premise reduces the probability of your thesis; and multiplying improbabilities compounds, such that a hundred together is massive geometric progression, trashing any probability you could have hoped for into effectively zero.

Hence the purpose, as stated, of chapters 4 and 5 (and 7), is to nail down what minimal set of premises can we be sure about, and then show what the results are on those premises. Yes, maybe many of those premises are false and we just don’t know it or haven’t proved it yet. But that doesn’t matter to the point, which is that, even on their own assumptions they should abandon historicity as a paradigm. That’s how you win arguments. You can’t throw a zillion wild claims at them and expect to get any traction. You need to do the opposite: keep any deviation to an absolute minimum, and then meticulously prove those. No other method is valid. Future scholars can then try to shift more. But you can’t shift a hundred things at once.

That’s explicitly stated as the study’s methodology and is consistently deployed throughout. The most conspicuous example is what I say about the dates of the Gospels. I have more to say on that in Ignatian Vexation (which is now in my book Hitler Homer).

Nevertheless, on this one point, I also happen to agree the mainstream view is more probably than not correct. While I am more sympathetic to the Marcionite Prioritists (who try to update the origins of Christianity to even after the Jewish War and/or its texts to the second century) and the High Chronologists (who argue for a c. 70 BC origin of Christainity), I remain unpersuaded by their arguments, and find just enough evidence against them to bolster the standard Low Chronology. It is at least > 50% the correct chronology, on evidence and logic. That doesn’t mean it’s > 99.99% the correct one, however. Hence I don’t consider the hypothesis ridiculous, just more or less false. But if I force-ranked these three chronologies, it’s probably: Low Chronology (the mainstream view), High Chronology (the pre-Roman view), Marcionite Priority (the post-War view).

it was still big enough to have different and competing sects a mere 20 years after its supposed starting date

What I see you falling victim to here is a common fallacy we need a name for. I’ve discussed it before with respect to arguments over the authenticity of Daniel: there is a tendency to see time differently the farther away something is. So, something that we readily recognize can happen in even a single year today, is somehow thought to require decades in antiquity.

Your “twenty years is not enough time” is an example of that. Why? Sectarian divisions can happen immediately, within days, certainly within years. They do not require even one decade, much less two—even less five or whatever. Mormonism officially began in 1830. On the death of Smith in 1844 it split immediately into several sects. So even just counting his somehow holding it together when alive (a thing less available to ancient operators, who will have completely lost control over anyone with new ideas a whole province or two away, or even another city or neighborhood away), that’s still a multisectarian split in under fifteen years. Where one sect existed, within days (not years), four did. The same happened to Scientology while Hubbard was still alive (they didn’t survive, but even the one surviving sect is barely still alive), likewise the Rajneesh movement. One could even say the explosion of UFO cults in the 1950s is an example, culminating in the most successful ones (the Raelians and Heavens Gate) which launched in the 1970s, less than 20 years from their forebears.

The readiness and speed with which new sects could form in antiquity is one of the reasons strongmen tried taking control of the Christian church in the 130s to 160s. A lot of what happened in that period is explicable as a struggle to control and limit the speed and divisiveness of schisms, by developing extreme slander and shunning campaigns and actual political moves to unify disparate sects into one loose affiliation to take over churches and get rivals killed or run out of town (and of course, deploying massive capex on the problem). This was why there was then a push to even have a canon and lock out access to authority claims by using historicity to lock in only those claiming apostolic pedigrees as legitimate (while denouncing anyone else claiming such to be faking it, when of course they probably all were), vs. several sects claiming a living voice of Jesus was still appointing apostles (this was the main reason Tertullian eventually turned on the Montanists to join the Pseudo-orthodoxists).

In short: things happen waaaaaaaaayyyyy faster than you inexplicably think they do. And your understanding of history must take that into account. What takes a few years now also took just a few years then. It didn’t get magically telescoped into a decades long trudge. Obviously anything could take that long. But it never had to. And it didn’t usually.

The early spread of Christianity is also very weird to me. We can usually explain people joining religions due to socioeconomic factors

Indeed. Read Element 29 in Historicity. I show that Christianity exactly fits, item by item, the entire criteria set in anthropology for the phenomenon of revolution cults throughout history. And Elements across chapters 4 and 5 (especially Elements 5, 13, and 23–29) demonstrate how the political situation was so apt that one could have predicted the rise and spread of Christianity a hundred years before, if they knew what they were looking for. It’s exactly on point to existing sociopolitical theories of religions and new cult crazes.

At least with the Greek mysteries you could explain it was in the realm of something they knew about

Case in point: you have the history exactly wrong.

First:

The Romans complained of how quickly “new cults” spread like wildfire and became popular. They were all alien cults, completely unknown and foreign until they showed up.

How did they do this? By packaging themselves in familiar veneer. So Isis cult did not rage across Rome because it was familiar, but because it was packaged in familiar things. The base example is the politically integrated Eleusinian cult of the Athenians. Every subsequent mystery cult adopted its trappings to evangelize itself effectively in foreign markets. That’s literally how mystery cults acquired the plural “cults.” And notice: that’s exactly what Christianity did. Indeed, it was a late comer to the party. Every other major culture had a multicultural mystery cult success story. It was just a matter of time before the Jews would.

Second:

In an environment that does not punish sampling—in other words, before abusive exclusivist religion gained imperial support (which did not happen until 325 AD)—spread of new religions is so common it actually creates the thing we call polytheism. Because of a psychological effect known for the spread of superstitions: because superstitions aren’t real, their success is stochastic, and thus fail eventually, driving an operator to switch to something new (believing it must have juice or it can’t hurt to find out). So, pray to Athena, get boons, feel good, then something goes wrong, look for a god that hasn’t failed you yet—hey, a god that drives people to travel hundreds of miles promoting it must be pretty effective, why else would they (yadayada), so let’s try that one. And because you are never punished for this, you can keep them all. You can go on believing in Athena while still trying out Cybele, and maybe that weird new god from Ethiopia is worth a look, and so on.

Empires thus accumulate gods and religions like junk in the attic.

Until they start punishing this. Then people are coerced to hew to only one and condemn all others. Which forces the zero sum decision as to which one will hurt less to adopt, which is typically going to be the one the empire rewards you for.

But that didn’t happen for a while. In the meantime, Christianity’s growth was limited by its exclusiveness to people who were so desperate or so moved or so bound to friends and relatives joining that they could justify going all in to get the bennies (usually food and friends and feels). Except the rich who then saw in it a way to become a big fish in a small pond (hence, early elite capture), and weak adopters (who could pretend to obey the exclusivity for as long as they could get away with it, and then their choice would be controlled by the cost of exposure or leaving, standard cult stuff even today).

These are all standard dynamics in textbooks on the psychology of religion.

In this context, Christianity fits exactly in its context. Which is not to say it was as successful as apologists claim. It likely won barely a few percent of the population before its imperial takeover.

And in that respect it was comparable to (and in fact largely built itself out of) Godfearers: pagans who already liked the idea of exclusivist Judaism and hung around it but just couldn’t mutilate penises or give up pork. When Jews became the “Enemy of the State,” Christianity became the best way into what they already wanted. And Gentile Christians had already leaned into that by eliminating the barriers to entry. So it accelerated growth in a normal fashion. The data show Christianity grew at about the same rate as Mormonism did (I cover this in the last chapter of Not the Impossible Faith). Which was another alien, heretical cult in its own persecuting imperial context.

There is a lot more to the story of why people join culture-defying cults like Mormonism or Scientology or the Cargo Cults or Falun Gong or Rastafari or Sevians or Raelians or Moonies, which also exactly match what Christians were doing and the context they were in. But hopefully you see enough of the point here.

Thank you. Your questions and followups have been good enough I might cobble this into a blog post with more links and citations.

As for the 20 AD thing: this conflicts with the Aretas datum. The only two dates that work for that are the 30s AD (for Paul writing in the 50s, getting the Aretas incident into the mid-30s) and the 70s BC (for Paul writing in the 50s BC, getting the Aretas incident into the 60s BC). I explain this in the linked discussion about the different arguments for standard high and low chrono. In short, high chrono has the advantage that it solves this, while low chrono complicates it but at least has the historical events of the Nabataean war, whereas changing the data decade up loses that advantage, so it becomes less probable than standard chrono. And so on. These are not conclusive. But it makes your thinking less probable than others, which have more evidence than you to point to. Since you already have to drop the Pilate framework, that leaves 70s BC more likely than 20s AD.

As for spread, there is no data that it spread any faster than any other religion in history. In fact its growth looks dead on standard for sociology of religion.

As for wealth, there clearly weren’t Peter Thiels in the early decades. There were some moneyed persons involved (Paul refers to them; congregations churched at their houses). But Paul being accused of graft constantly indicates that they had only small fish on the hook, no one with real juice; and Paul appears to have been the wealthiest member of the movement at the time, and even he had to hustle, so he wasn’t that rich.

Pliny the Younger’s trials also indicate no major players connected as of the 110s. The first time we see any evidence of serious big fish getting involved is Marcion, which is the 130s, a century after the cult began. And it appears his impact was precisely that this was the first time a Peter Thiel type moved in on the religion, sparking the panic: if there was going to be elite takeover, there were opinions about which elites that should be, just as there are camps today that side with Thiel or Musk against each other; and so the division between Marcionites and the consolidation of an anti-Marcionite league began, essentially originating modern orthodoxy as a reactionary political move. Likely on that side it moved up the ladder of client-patron relationships to recruit a group of big fish in exchange for power and influence in the movement. Selling their soul to win, as it were.

Footnote: I’ve guestimated Marcion at billionaire status but it might safer be said “tycoon status” at over a hundred million maybe over a billion. I calculate the dollar adjusted value of silver coins in Science Education, 52 n. 125, which is already out of date due to skyrocketing US inflation, but since minimum wage has not budged (even though it should be at least $15 it remains at just over $7), the math is still the same. But running for either value, Marcion’s 200,000 sesterce donation has a modern lowball value of almost six million now; but really, price adjusted, twelve million. That’s unlikely to have been even a twelfth of his net worth as a major shipping magnate (the standard annual interest rate then, so a minimum year’s passive income for him). So at minimum he was a mega-millionaire at over 144 million net worth. Would he give away a year’s income? Probably not. If his donation was 1% of his net worth, the latter would have been 1.2 billion. Either way he’s very big fish. Nothing like the few upper middle class donors Christians were tapping in the early days.

That’s what I mean.

Paul had to have converted by his own chronology within a few years of the religion, because Jesus remains the firstfruits of the general resurrection (so decades cannot have passed by then; in fact by Danielic logic, no more than seven years could have, and more likely it was less than three) when Paul’s revelation closed the loop, making him “last.” So his own chronology puts the Peter vision (starting the cult) in the 30s AD (or 70s BC on the only other viable model), because the letters then date to the 50s (AD or BC) by his own internal chronology (Acts is useless so its chronology should be ignored). Paul then started writing letters after the imminent end did not come and he had to pivot to keep his congregations together (this is why many conclude 1 Thessalonians was the first written, and Galatians close second).

It gets difficult and awkward to shift the chronology by decades either way, and that is going in the wrong direction on the probability curve.

Actually I present evidence in OHJ that the Daniel prophecy was the thing driving messianic fever exactly then. It’s even mentioned by Josephus. It is already being discussed at Qumran. It was not applied after the fact.

The expectation that a messiah would die, beginning a seven year end-times clock was so locked in it was a common Jewish belief by the time of Paul. My recent study confirms this across a wide range of scholarship.

This is what Paul is referring to when he says Jesus is the first part of the general resurrection: the death itself began the period of resurrection of all Israel (a concept found in only one place: Daniel 9 & 12), with only a brief pause to bring in the elect. Jesus is not an isolated special resurrection. His resurrection is the resurrection, beginning it.

That is not a belief that could be held decades after the fact. By then, Paul would need to come up with some other framing than that. The idea that the end was in progress required mere years of distance to actually say Jesus began the resurrection of everyone. Paul would only then be locked into repeating but reinterpreting it decades later.

But there are direct references in Paul: 1 Corinthians 6:2 references Daniel 7:18–22, 1 Thessalonians 4:17 references Daniel 7:13, and 1 Thessalonians 4:13–16 and 5:10 and 1 Corinthians 15:40–42, 51–52 and Philippians 2:15–16, etc. reference Daniel 12:1–3 and 7:13–14. Likewise Dan 2:21 is referenced in 1 Thess 5:1.

This is all in alignment with the Melchizedek Scroll, a pre-Christian pesher on Daniel 9, which originates many of the themes Paul takes for granted above (celestial messianism, imminent apocapyticism, describing the risen messiah as an archangel, the short timetable after the death, including placing the death seven years before the resurrection of all Israel, etc.).

So, no. This originated Christian thinking, right in line with pre-Christian Jewish sectarian thinking all around them, particularly among sects the Christians were most like and thus most likely originated from or were influenced by. It was not discovered after the fact. It was a cause of Christianity. Not an effect.

All the well-known ones I am aware of are too accepting of the traditional narrative to my taste and are all firmly historicist (which is to be expected).

I sympathize. That we need the thing you are asking for is precisely what Obsolete Paradigm was written to explain and encourage. The field is ignoring it. So it won’t give you one. And I don’t have the time or resources to do it myself, unless it was with a team of scholars sharing the labor and dovetailing their specializations.

Vinzent also wrote a whole book arguing that we need the thing you are asking for. He is also being ignored.

So, that’s where things are. I don’t see it changing anytime soon.

The closest you’ll get is almost useless hodgepodges like The Next Quest, which fails because it simply assumes historicity and mostly traditional narratives, and produces no coherent comprehensive result but just a random candy bag of microtopics.