Anarcho-syndicalism? No. A work of writing? No. Recipe? No.
A clarification: I believe my "yes" answer to "Created by humans?" is the least misleading but I suppose proponents of this -ism might dispute my answer.
Idealism? No. Anti-? No. Spiritual? Another interesting question. The best answer is No, though I'd caution that "spiritual" admits of multiple definitions. The AOTC is spiritual-adjacent, however Crackpot? If you presented the AOTC to random people on the street, most would agree with that descriptor. If you asked those with more specialised knowledge, some would certainly still agree; the majority would disagree with the AOTC without (I think) necessarily being so pejorative. I hope that helps. :)
Veganism? No. AI? No. (*a few glances exchanged in the audience, but no actual applause*) Dianetics? No. Geography? No. Geology? In some sense maybe Yes, but that's unlikely to be helpful. Related to Art? No.
We know that this is an ISM and refers to to something that was invented by humans, and that's about as far as we've got. We do know that it doesn't begin or end with p, c, or anti. It has nothing to do with geography, geology, art, literature, or astronomy. It's not veganism, idealism, creationism, or dianetics, nor is it named after a person. There is a possible tenuous link to religion/spirituality, although all the guesses so far have not led anywhere. Normal people will think that the AOTC is crazy, those with more specialised knowledge will think that it doesn't work, although it still has its supporters.
Recap. Mostly correct, although you only know that it doesn’t begin with C or end with P. I struggled with my answer to “invented by humans?”, so I’ll attempt a clarification. If we think of, say, a continuum of isms from Marxism (clearly invented by humans) to magnetism (clearly not), I think this is a bit closer to Marxism. But it is something that humans have thought of that could conceivably be fact—and if it were fact, it would be more like magnetism. Economics? No. Aliens? No. Contain the name of a being? No. (Well, technically yes, but that’s essentially coincidental). Politics? No.
One more clarification. B’s recap stated “those with more specialised knowledge will think that [the AOTC] doesn’t work”. I’d say,rather, that they’d think it isn’t true.
1.6 billion? I think that the adjacent spiritual/religious concept quite probably has more than that number of adherents. The AOTC is a more technical notion (and term), which would be unfamiliar to (most of?) those adherents. I think. The adjacent spiritual/religion-adjacent concept might be a helpful route to the answer. Governmental? No. Associated with a particular group? For the AOTC itself, I'd say No. But the adjacent spiritual/religion-adjacent concept is certainly associated with various identified groups.
Corporeal? The best and least misleading answer is No. (There is a pedantic sense in which the answer is Yes, because “anything to do with” is pretty broad and vague.)
Idea about the nature of the entire universe? Yes! *sustained applause* To do with logic? No. Relate to death? The best answer is No, though an indirect argument could be made for Yes.
University Philosophy? I'm not an expert in university philosophy curricula, but I'll speculate as follows: the AOTC would show up somewhere in the curriculum but is unlikely to make an appearance in an Introduction to Philosophy subject. The AOTC has an entry in the Internet Encyclopedia of Philosophy, the Stanford Encyclopedia of Philosophy, and Britannica. Plato's cave? No. Has anyone said Existentialism yet? No. Is Existentialism the AOTC? No. (I'd put that more in the vicinity of Spiritualism on the M-m scale.) Does it entail a belief in predestination? You just had to ask that, didn't you? No.
Enjoying this? Yes and No. Whenever an AVMA takes this long, I worry that either I have made it too hard or that I have inadvertently misled people with a less than perfect answer. Old Greek? The idea of the AOTC can in some sense be traced back to the very earliest days of recorded philosophy, which of course includes quite a few old Greeks. That said, I don't think the AOTC is associated with a particular OG who was a "major proponent". (It's not like, say, stoicism, where—if you know about the topic—you'd immediately link it to Epictetus.) Simulation hypothesis? No.