Imagine a device that you put on your head and press "record". After 5 minutes, you press "stop" and then I put it on my head and press "play". I then experience those 5 minutes as you experienced them. You could also replay your own 5 minutes and confirm the recording is accurate.
That device doesn't exist today -- it's sci-fi -- but there's no known law of physics that forbids it. If it is built it would be a lot of progress towards, perhaps even a solution for, the hard problem.
The only realistic way we either build that device or prove that it can't be built is science (probably neuroscience). So, my opinion is that, to a large degree, when we opine about "subjective nature of experience" we're bloviating a bit. Our experience is subjective now but there's no law of physics that says that must always be true.
Anyway, if someone claimed to create such a machine I would, in fact, very much doubt that it actually creates the same experience simply because no human brain is quite physically the same, so it will interact differently with the machine. That's true even if experience is entirely physical.
> The only realistic way we either build that device or prove that it can't be built is science.
There's another possibility: the device remains in the realm of hazy infeasibility forever, where no one succeeds convincingly but we also never articulate why it's impossible. I think this is more likely. Certainly the engineering would be extremely difficult.
Any candidate device will face the usual objections about the relationship between experience and its physical correlates, plus the one I mentioned above about physical differences between brains, and probably a dozen more depending on the details. You'll be able to choose to believe it proves consciousness is physical, or not, but you can already choose that today with equally strong evidence. It's like a binary Rorschach test for your assumptions about metaphysics.
If we understood conscious experience well enough to capture and replay it so closely that the person who had the experience could verify it, then almost no one would care about the hard problem.
Sure, there'd be a speck of doubt. But if the removal of all doubt is required to solve a problem then no problem is soluble.
> There's another possibility: the device remains in the realm of hazy infeasibility forever, where no one succeeds convincingly but we also never articulate why it's impossible. I think this is more likely. Certainly the engineering would be extremely difficult.
That's where we are now. And we should just admit it, instead of claiming that "consciousness is inherently subjective" or whatever.
> Any candidate device will face the usual objections about the relationship between experience and its physical correlates, plus the one I mentioned above about physical differences between brains, and probably a dozen more depending on the details. You'll be able to choose to believe it proves consciousness is physical, or not, but you can already choose that today with equally strong evidence. It's like a binary Rorschach test for your assumptions about metaphysics.
What equally strong evidence exists today? Comparing it to a rorschach is absurd. I worry your view amounts to epistemological nihilism. The vast majority of peope would admit that we had a thorough understanding of consciousness if we could record and replay it, two things we certainly can't do today.
Back in the XVII/XIX century, a similar problem existed regarding life - the problem of "what makes living things tick". The assumption at that time was that while we can understand the biological processes around life, we will never understand the so-called "vital force", which causes things to live - life itself. I know it sounds weird now, but back in the day the mental models were different. Phenomenas like "water boils" and "organisms self-replicate" were treated as completely different domains of reality, without an overarching uniform scientific model.
It turned out that after around 100 years, we can figure out the chemical/physical processes and the need for the term "vital force" became redundant.
While this is certainly not an argument proving that the Hard Problem is not in fact hard, it is an interesting idea to think about. Perhaps its all a matter of developing better, higher-resolution neurological models which will at some point give us the tools to decompose qualia.
Even if we were to e.g. identify some field that seemed to coincide with entities reporting a subjective experience, we wouldn't have a way of determining if they truly do, or just act as if they do, nor is it clear such entities would be able to report the difference.
As it is, we struggle to quantify even much more basic differences in experience that we can introspect. E.g. I have aphantasia - I don't see things in my minds eye - and I regularly come across people who insists both that can't be true, and that it can't be true that others see things. And some of the people I've spoken to who insist aphantasia isn't real clearly has it based on digging into their thinking about it.
Even at that level we rely on trusting people's claims about their introspection - we don't know, we assume based on testimony.
Anyway, further reading: https://en.wikipedia.org/wiki/Vitalism I was in fact looking this up recently for fiction-writing purposes.
What we could do is break down other facets of what we talk about under the umbrella of consciousness, and find measurable subsets.
E.g. a lot of people insists LLMs can't reason either. Coming up with a testable definition of what that means might be doable.
Overall also just separating the subjective experience from the rest leaves us in a position where proving the possibility of AGI "just" rests on whether or not human brains exceed the Turing computable.
If they don't, then subjective experience or not is irrelevant for the question of reasoning and intelligence, as in that case a subjective experience either can't affect the computation or must itself be at least possible to fully simulate by any Turing complete system.
The problem of subjective experience then would largely be down to faith and feelings but would also be entirely orthogonal to the rest.