I think there could be a 5% chance that the paleocene-eocene thermal maximum 55 million years ago was the result of a prior global industrial civilization.  Conditional on that being the case, high probability they were birds and a decent possibility they lived on Antarctica.

We are an existence proof for smart industrial animals being a thing that can happen on Earth.  We are not an existence proof of smart industrial animals lasting for geologically long periods of time.  There is not necessarily reason to think that just because you are successful in an epoch that you burn the black rocks that you will continue to be so.

As you go back in time the fossil record degrades drastically and many species at this time are known from single digit numbers of specimens.  The PETM resembles what we are doing to the earth system entirely too closely, from a large release of biogenic carbon within a few thousand years to the spike in mercury levels to ocean anoxia.  At the time primates did not exist in significant diversity and any that did exist were tiny, but birds, whose brains differ from the default tetrapod brains in ways quite similar to the way that of primates do and allows very easy increase in neuron number, did exist in profound diversity. 

We are tropical animals and spread across the entire world because we came from the hottest place on Earth and you can keep us warm just by wrapping us in clothes in a low-tech way.  If somebody evolved on the coldest parts of Earth, you need high technology (refrigeration) to survive anywhere else and they could be limited to polar latitudes, including the only continent we have almost no geological record of and has been poorly explored - Antarctica.  Antarctica and nearby continents also bore multiple great-ape-sized flightless bird lineages at this time, and was temperate while Canada was full of Amazon-style rainforest and the equator bore stifling hot supertropics.

Corollary:  Industrial civilization is an unstable self-limiting phenomenon and will be gone in centuries to millennia.

Jeffrey Epstein didn't commit suicide. Two cameras malfunctioned, the normal procedures weren't followed, and it's silly to think he didn't have compromising information on important people. And it was an incredibly high-profile prisoner. 

"Attorney General William Barr described Epstein's death as 'a perfect storm of screw-ups'." Yet several guards were indicted on charges of conspiracy and record falsification.

This belief is so obvious to me that I felt like I was being gaslighted by news outlets and even academics who later called the belief a conspiracy theory in the same class as QAnon and UFOs, including a guest on a FiveThirtyEight podcast about conspiracy theories (I'm a huge FiveThirtyEight fan; they laid the groundwork for me to appreciate this community, which in turn mostly increased my appreciation for FiveThirtyEight).

A majority of Americans seem to agree with me, although who knows why, so maybe it's not a "weird" belief except when compared against the mass media/"elite" narrative.

You could de-convince me with statistics about how often those and similar cameras malfunctioned and how often guards disregarded normal procedures with other prisoners, low profile and high profile. 

External reality is not a meaningful concept, some form of verificationism is valid. I argued for it in various ways previously on LW, one plausible way to get there is through a multiverse argument.

Verificationism w.r.t level 3 multiverse - "there's no fact of the matter where the electron is before it's observed, it's in both places and you have self locating uncertainty."

Verificationism w.r.t. level 4 multiverse - "there's no fact of the matter as to anything, as long as it's true in some subsets of the multiverse and false in others, you just have self locating uncertainty."

Lots of people seem to accept the first but not the second.

That governments should, over the long term, run balanced budgets. ie there are many good reasons for a short term budget deficit (global crisis, natural disaster) but governments should budget to return to government surplus as soon as possible and pay down debt (eg to something like 20% GDP).
This obviously doesnt seem weird to me, but people from MMT theorists to heads of world major economies think it is.
Why do I believe that? Well we (New Zealand) had major reforms of economy and government in 1980-90s. At time, (showing my age) I thought it is was madness and seriously, morally bad. However, once the pragmatists replaced the ideologues, it now seems to me that the residuals of the reforms (including the balanced budget requirement) has delivered a strong and resilient economy. Various crises have been managed well because the government has been in a strong fiscal position to start with.

Have I really examined or tested this belief? Nope. I find many things more interesting than economics and whether the belief is right or wrong doesnt impact on anything I do, including voting. The policy has cross-party support so unless I vote for a fringe party, then I am voting for this anyway. 

I think a large number of people would benefit from temporarily adopting a mystic/magical religion. Tantra comes to mind first owing to David Chapman's writing, but Wicca, alchemy, Kabbalah and ritual magic are included as well. 

These are systems utterly at odds with normal and socially acceptable modes of living. Ideally, these could serve as shocks to break people out of major ruts in thinking or belief, or as outlets for resolving emotional hangups and releasing socially unacceptable desires. I also know a good few people who, if nothing else, could really use an injection of weirdness and wonder to break them out of self-imposed boredom. The exact system matters less than the presence of a system at all. 

The key is not to get too caught up in them or start believing they're real. So long as they maintain a playful aspect, you're probably fine. You also want to avoid getting into cults, especially Scientology. They're also weird, and they're also systems of meaning-making, but they take themselves too seriously and in the latter case it's difficult and potentially harmful to leave. 

Distinguishing cults from playful religions may be much more difficult than I'm giving credit for. Keep an exit strategy on hand and don't give out your credit card information.

Not sure if it counts as a "weird belief" but I am an anarchist for relatively "usual" reasons.

I believe Plants, Fungi and even inanimate objects experience consciousness (to some extent). Consciousness is, probably, an intrinsic property of matter and it exists throughout the physical universe in some form.

Taking information hazards seriously.

This can range from the benign (is it a good idea to post very weird beliefs here?) to the more worrying (plausible attacks on $insert_important_system_here), and upwards.

-

I believe in "supernatural phenomena" due to many anecdotal experiences I personally had. I do acknowledge they may all be me incorrectly evaluating ordinary natural phenomena or mental processes due to psychological quirks of mine. Hence, I make a constant effort to no let them interfere in anything I'm dealing with that has clear scientific consensus and/or hard data, or in my ethical, social, and political standings, preferring to keep both sides well separated. In short, to use LW terminology, I willfully compartmentalize.

However, I do not believe in separate magisteria. I'm confident that eventually either the mechanisms behind those experiences I have had will be well known, solving the confusion in a definite way, or those phenomena will be consistently observed, studied, scientifically understood, incorporated into physics, and turned into useful technologies.

Funnily, I'd have preferred not to have had those experiences, as I really like transhumanism and its projected future possibilities, such as cryonics-based resurrection, cognitive reengineering, uploading, mind splitting/remerging/backing up/restoring, and others, all of which becomes from extremely unlikely to impossible if what I've experienced is real. As such I don't see these, all things considered, as a net positive.

I think that we should be taking the possibility of UFOs more seriously. Over the last year, I've updated from thinking that UFOs are laughable to thinking there's a 10-20% chance of actual alien visitation, and about another 10-20% of something else important going on. (Ie someone - presumably China - has either made a huge leap in drone technology or is getting good at spoofing multiple US military systems simultaneously.) 

Why? Because a number of senior and generally sane people seem to be taking this seriously. The US military forces in particular are seeing a number of cases of unidentified phenomena - not just aerial, also submarine - where they see things that look like craft that have capabilities not currently possible with modern technology. Some of these things like the 2004 USS Nimitz incident have been captured on multiple systems like the ship's radar, and aircraft cameras and visually spotted by the pilots. The former Direction of National Intelligence has said recently that there are a lot more sightings which haven't been made public.

Yes, I know there are still other explanations, and the track record suggests sightings will turn out to be some kind of optical illusion or something, but I'm open to the possibility that not every incident is explicable in terrestrial terms.

The link below is a good long-form read which argues that the US Department of Defence is taking the possibility seriously.

https://www.thedebrief.org/fast-movers-and-transmedium-vehicles-the-pentagons-uap-task-force/
 

Doomsday argument and quantum immortality are both true, and it means that I will be the only survivor of a global catastrophe. Moreover, it will be in a simulation.

Both DA and QI could be tested in other fields. DA was tested to predict other things besides the end of the world by Gott. QI is anthropic principle applied to the future. 
Aranyosi claimed that DA and Simulation argument cancel each other, but actually they support each other: I live (or will live because of QI) in a simulation which simulates a doomsday event with one survivor.

None of my beliefs feel weird to me - I find it weird that many/most people seem to believe different things.  

For this site, I'll go with radical anti-realism.  All value is personal and relative - there is no objective view or measure about moral decisions.  Crowley had it right (on this point; he was wackadoo on others) "Do what thou wilt, and then do nothing else".

It cannot be stated with >99% certainty that members of the Bush Administration did not have definite prior information of the events of 9/11 or played a role in it.