Pattern-chaser wrote: ↑August 7th, 2022, 11:42 amSorry, you've just answered my question (above). OK. ... But Objectivity — 'mind-independent correspondence with that which actually is' — cannot be confirmed (or denied) via "rationality, logic, and deduction". For example, if I thought that we might be brains-in-vats, how would you use these tools to confirm or refute my suspicion? [Remembering that the 'reality' we experience as brains-in-vats is completely identical to what we would experience in a world where 'reality' actually is what our senses show to us.]
Yes — Objective Reality: 'that which actually is, mind-independently'.
The question here is whether we have access to Objective Reality. We don't, not knowingly. [We could, in theory, stumble across Objective Truth — that which exhibits 'mind-independent correspondence with that which actually is' — coincidentally, but we have no way to demonstrate we have done so, to ourselves or to each other.]
Again, you miss my point. Whether we are brains-in-vats is not a theory. Or at least, it's not presented as such. It is presented as a thought experiment, an illustrative example. And what it illustrates is that we have no way to tell if we are brains-in-vats, or maybe that the apparent reality that our senses seem to show to us is Objective Reality.
You are correct that there are no reasons for "most people to believe in that theory". That's the point: there are no such reasons, just as there are no reasons to believe that Apparent Reality is Objective Reality. And, just as there are no reasons to believe, there are no reasons not to believe either. There is no evidence for or against; none at all.
Lacking evidence, as we do — there is none; none at all — no form of scientific or philosophical analysis is possible, and therefore no conclusions may logically be drawn. It is impossible to say, according to scientific or philosophical standards of any sort, that the idea behind this thought experiment is true or false. No reason to accept; no reason to deny.
Btw, the brain-in-a-vat idea is possible. I would not use the word "probable", as there are no statistical means by which such a probability could be quantified. And even if it was the Objective Truth, there would not be "clear and obvious indications for such a theorem". You assume and assert that there are, but how could there be? Being brains-in-vats is scientifically and philosophically indistinguishable from any alternative explanation (thought experiment).
What scientific or philosophical principles or knowledge confirm this? You blithely refer to believability, implying that you have some basis to determine "believability". What is this basis? I will echo your words: "Is it scientific? Is it empirical?" Or is it, simply, imagined, and asserted without foundation or justification?
No, not that I know of, except as an illustrative example of possibility. No. No. Yes (I'm not sure about "solipsistic" though).
But let's complete the sense of my position, and paraphrase you again, with a balancing example:
Is Apparent Reality theory relevant? Is it scientific? Is it empirical? Or is it, simply, subjective wishful thinking?