They all seem to be asking variants on the question "how likely is apparent reality real?". They also all seem to have weird properties as far as evidence is concerned, because the observable evidence must all come from the very source (observed reality) whose credibility we're questioning.
Also, except for the solipsism one, they seem to be questions where, contrary to LW canon, it might be a good idea to deliberately self-delude (by which I mean, for instance, not bothering to look at the evidence in-depth). If I really felt a .5 probability in my bones that I was living in a simulation, I don't think I'd be able to work as hard at achieving my goals; I wouldn't have as much will to power when it could all disappear any moment.
Aside: I'm genuinely surprised at the lack of discussion of lucid dreaming on LW. Lucid dreaming seems like a big gaping loophole in reality, like one of the elements you'd need in a real-life equivalent of the infinite-wish-spell-cycle, yet nobody seems to be seriously experimenting with finding innovative uses for it.
In hindsight, though, it seems like removing the middle question might have been better.
I would like to be working on lucid dreaming research but am unaware of any avenues towards obtaining the very expensive MRI time to do it.
Often, there are questions you want to know the answers to. You want other people's opinions, because knowing the answer isn't worth the time you'd have to spend to find it, or you're unsure whether your answer is right.
LW seems like a good place to ask these questions because the people here are pretty rational. So, in this thread: You post a top-level comment with some question. Other people reply to your comment with their answers. You upvote answers that you agree with and questions whose answers you'd like to know.
A few (mostly obvious) guidelines:
For questions:
For answers:
This thread is primarily for getting the hivemind's opinions on things, not for debating probabilities of propositions. Debating is also okay, though, especially since it will help question-posters to make up their minds.
Don't be too squeamish about breaking the question-answer format.
This is a followup to my comment in the open thread.