[Link] First almost fully-formed human [foetus] brain grown in lab, researchers claim
This seems significant:
An almost fully-formed human brain has been grown in a lab for the first time, claim scientists from Ohio State University. The team behind the feat hope the brain could transform our understanding of neurological disease.
Though not conscious the miniature brain, which resembles that of a five-week-old foetus, could potentially be useful for scientists who want to study the progression of developmental diseases.
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The brain, which is about the size of a pencil eraser, is engineered from adult human skin cells and is the most complete human brain model yet developed
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Previous attempts at growing whole brains have at best achieved mini-organs that resemble those of nine-week-old foetuses, although these “cerebral organoids” were not complete and only contained certain aspects of the brain. “We have grown the entire brain from the get-go,” said Anand.
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The ethical concerns were non-existent, said Anand. “We don’t have any sensory stimuli entering the brain. This brain is not thinking in any way.”
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If the team’s claims prove true, the technique could revolutionise personalised medicine. “If you have an inherited disease, for example, you could give us a sample of skin cells, we could make a brain and then ask what’s going on,” said Anand.
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For now, the team say they are focusing on using the brain for military research, to understand the effect of post traumatic stress disorder and traumatic brain injuries.
http://www.theguardian.com/science/2015/aug/18/first-almost-fully-formed-human-brain-grown-in-lab-researchers-claim
To know what I'm referring to by a term is to know what properties something in the world would need to have to be a referent for that term.
The ability to recognize such things in the world is beside the point. When I say "my ancestors," I know what I mean, but in most cases it's impossible to pick that attribute out empirically -- I can't pick out most of my ancestors now, because they no longer exist to be picked out, and nobody could have picked them out back when they were alive, because the defining characteristic of the category is in terms of something that hadn't yet been born. (Unless you want to posit atypical time-travel, of course, but that's not my point.)
So, sure, if by "flying saucer" I refer to an alien spaceship, I don't necessarily have any way of knowing whether something I'm observing is a flying saucer or not, but I know what I mean when I claim that it is or isn't.
And if by "consciousness" I refer to anything sufficiently similar to what I experience when I consider my own mind, then I can't tell whether a rock is conscious, but I know what I mean when I claim it is or isn't.
Rereading pangel's comment, I note that I initially understood "we don't know actually know what those concepts refer to" to mean we don't have the latter thing... that we don't know what we mean to express when we claim that the concept refers to something... but it can also be interpreted as saying we don't know in what things in the world the concept correctly refers to (as with your example of being wrong about believing something is an alien spaceship).
I'll stand by my original statement in the original context I made it in, but sure, I also agree that just because we don't currently know what things in the world are or aren't conscious (or flying saucers, or accurate blueprints for anti-gravity devices, or ancestors of my great-great-grandchild, or whatever) doesn't mean we can't talk sensibly about the category. (Doesn't mean we can, either.)
And, yes, the fact that I don't know how subjective experience comes to be doesn't prevent me from recognizing subjective experience.
As for urgency... I dunno. I suspect we'll collectively go on inferring that things have a consciousness similar to our own with a confidence proportional to how similar their external behavior is to our own for quite a long time past the development of (human) brains in vats. But sure, I can easily imagine various legal prohibitions like you describe along the way.
I meant it in the sense you understood first. I don't know what to make of the other interpretation. If a concept is well-defined, the question "Does X match the concept?" is clear. Of course it may be hard to answer.
But suppose you only have a vague understanding of ancestry. Actually, you've only recently coined the word "ancestor" to point at some blob of thought in your head. You think there's a useful idea there, but the best you can for now is: "someone who relates to me in a way similar to how my dad and my grandmother relate to me". You go around telling people about this, and someone responds "yes, this is the brute fact from which the conundrum of ancestry start". An other tells you you ought to stop using that word if you don't know what the referent is. Then they go on to say your definition is fine, it doesn't matter if you don't know how someone comes to be an ancestor, you can still talk about an ancestor and make sense. You have not gone through all the tribe's initiation rituals yet, so you don't know how you relate to grey wolves. Maybe they're your ancestors, maybe not. But the other says : "At least, you know what you mean when you claim they are or are not your ancestors.".
Then your little sisters drops by and says: "Is this rock one of your ancestors?". No, certainly not. "OK, didn't think so. Am I one of your ancestors?". You feel about it for a minute and say no. "Why? We're really close family. It's very similar to how dad or grandma relate to you." Well, you didn't include it in your original definition, but someone younger than you can definitely not be your ancestor. It's not that kind of "similar". A bit of time and a good number of family members later, you have a better definition. Your first definition was just two examples, something about "relating", and the word "similar" thrown in to mean "and everyone else who is also an ancestor." But similar in what way?
Now the word means "the smallest set such that your parents are in it, and any parent of an ancestor is an ancestor"..."union the elders of the tribe, dead or alive, and a couple of noble animal species." Maybe a few generations later you'll drop the second term of the definition and start talking about genes, whatever.
My "fuzziest starting point" was really fuzzy, and not a good definition. It was one example, something about being able to "experience" stuff, and the word "similar" thrown in to mean "and everyone else who is conscious." I may (kind of) know what I mean when I say a rock is not conscious, since it doesn't experience anything, but what do I mean exactly when I say that a dog isn't conscious?
I don't think I know what I mean when I say that, but I think it can help to keep using the word.
P.S. The final answer could be as in the ancestor story, a definition which closely matches the initial intuition. It could also be something really weird where you realize you were just confused and stop using the word. I mean, the life force of vitalism was probably a brute fact for a long time.