The problem is that if we accept the possibility that we're brains in jars, the vast majority of our information becomes unprovable.

Yes, this can occur from believing the answers to unanswerable questions. This isn’t unique to the philosophical brain in a jar scenario, it’s applicable to practically any question that is unanswerable. Basing logic on the answer to an unanswerable question leads to rabbit holes.

I can't disprove the strong skeptical hypothesis, therefore I can't know anything that would be disproven by the strong skeptical hypothesis.

What happens when you try to prove a proposed answer to an unanswerable question? Why try to prove or disprove the “brains in a jar” scenario when it’s unprovable? Do you accept that some questions are unanswerable and that the answers to unanswerable questions are unprovable?

What we know is multi-factorial and begins on a subjective level with sound parameters and practices (like repeatability and other scientific methods) and is confirmed or verified on a shared level. Unprovable scenarios like “brains in jars” can be suggested and can reveal more about unprovables than it does a commonly accepted truth in a commonly accepted shared reality.

I don't think it's an either/or between belief and knowledge. After all, anything I know is also something I believe.

If it is your agenda to say that you believe all that you know then this is just your perspective. I know that I have 5 fingers on my right hand. If you understand and accept the meanings of the words “I have 5 fingers on my right hand”, we occupy the same space in commonly shared reality, and you exist on a human wavelength then upon proving to yourself that I have five fingers on my right hand this information would become knowledge to you without requiring belief. And yes, even then if your agenda is to base all you know on belief then you can do this and I cannot disprove what you believe nor your ability to believe. But then this just says more about you as a person than it does me or commonly shared reality.

What I'm proposing here is that we can have solid justification for holding a belief even in absence of knowledge or proof that the belief is true. On the brain in a jar scenario, I'd say that I can't disprove the hypothesis but that I don't have justification for believing that hypothesis. Between the positions of belief and disbelief, I think that the reasonable position here is disbelief.

People can and do believe whatever they want to, and what people do believe is usually aligned with their bias and agenda.

If I premise other beliefs on this non-knowledge disbelief of strong skepticism, I'd similarly say those beliefs are not knowledge, but nor are they just things that I happen to believe. They're "reasonable beliefs": the most reasonable positions I can take given the evidence I have, even if I don't possess knowledge.

They are unprovable regardless of reasonability.

Either we have to accept that we have minimal knowledge…

I’ve already accepted this. I would rather accept something is unprovable rather than make stuff up and then believe or disbelieve it’s true. This doesn’t mean I won’t entertain far out thoughts, rather my basis or starting point is one of knowing that we may never truly know the answer to unanswerable questions.

If we accept the former, we need some other epistemological basis to describe the majority of what we would like to say we "know".

I think where I describe in my last comment what I know and how you can know it too meets my criteria. It works for me. It’s basically what currently exists, ideally where everyone agrees to leave others to their own beliefs as long as it doesn’t harm others. If one wants to drink the koolaid then that’s on them, if they want to convince others to do that then I have an issue.

Edit Having said that, I understand the creative process behind discovery of the unknown and how technology and what is commonly accepted as being known is revealed/illuminated. If we limited ourselves to what is known then there may be little to no progress and advancement. I am mainly focused on pointing out unprovable philosophical scenarios and how they may prove to be good mental exercise in a way, but anything beyond working to understand and moving towards skewing to believe and I’ll pass.

Edit2 I know things and am open to being wrong. I understand now that I’d rather write something off as unprovable rather than participate in choosing either belief or disbelief.

Allow me an opportunity at a different approach.

The incompleteness theorem states that in any reasonable mathematical system there will always be true statements that cannot be proved. Responses to this theorem have been varied. Some people have proposed that if we demand that the standard of proof in the sciences is mathematical certainty and math is not 100% entirely provable then absolutely nothing is certain. While the incompleteness theorem presents a problem for those that want math to be entirely provable, this theorem only applies when self-referencing in a negative. So, as of now, math is provable except in this specific paradoxical self-referencing scenario yet people still claim that all math is now suspect despite it’s accepted provability.

I would rather judge a situation’s provability first before participating in likelihood of occurring or being real. It’s unprovable whether we are or are not brains in jars and that is my ultimate position, but if I were forced to choose I would lean unlikely. Do I believe it’s unlikely? No, I think it’s unlikely. First and foremost, it’s unprovable either way.

Would you happen to have access to this journal?

https://www.cambridge.org/core/journals/behavioral-and-brain-sciences/article/abs/knowledge-before-belief/B434EF04A3EA77018384EABEB4973994

While many philosophers may agree that knowledge depends on true belief, I see that not everyone does. It seems to be a semantics game, each side clamoring for their specific words choice to become primary.

• A philosophy professor of mine once asked me if I knew that George Washington crossed the Delaware.*

My response would be “it’s been mentioned in history books so there may be truth to this story.” If the professor pushes me to choose belief or disbelief in the story I would push back against participating in belief or disbelief. I would much rather report on the origin or state of communicated beliefs rather than participating in choosing to belief or disbelieve.

In your second example you speak as if you may have read about Washington’s crossing being propaganda or intentional misinformation and then how you could believe what you read. Again, I would state what is written or even accepted by others without taking the next step of believing (or disbelieving) it myself.

Edit I can speak about things without participating in believing or disbelieving