Why wouldn't there be any possibility of artificial human intelligence? Our intelligence is just a manifestation of a physical system of neurons that follow the laws of physics. There's nothing inherently preventing us from recreating that.
>>Why wouldn't there be any possibility of making artificial humans? We are just a manifestation of a physical system of bonds between organic molecules that follow the laws of physics. There's nothing inherently preventing us from recreating that.
Obviously, such a summary vastly oversimplifies the problem. It is easy to look at how far we've come and think that we must be close to the goal, but it's a bit presumptuous to think that we are near to making a strong general AI.
But I don't think they're presuming that. They're simply saying that it's possible in principle. How long it takes, and whether indeed we ever manage it all, are separate questions.
In principle, everything is possible, but some things are so unlikely, that it is reasonable to label them as impossible.
The computer technology we have developed over the last 75 years is so fundamentally different from how our minds work that to think we will develop anything resembling our own intelligence in any reasonable time-frame is insane.
That doesn't mean we can't develop a machine that is able to reason for itself and solve discrete problems. We can. That's not what AI is. AI is Artificial Intelligence. An artificial intelligence defined by us.
There are some things which I think it's reasonable to consider impossible in principle: e.g., FTL travel, time-travel into the past. (That's not to say it would be necessarily unreasonable to hold the opposite view).
And that's the crux of the question isn't it? How do we determine if the intelligence is recreated or merely mimicked? Does such a distinction matter? Searle says yes. More here if you're interested: http://plato.stanford.edu/entries/chinese-room/
From the linked article on the Stanford site:
> Searle imagines himself alone in a room following a computer program for responding to Chinese characters slipped under the door. Searle understands nothing of Chinese, and yet, by following the program for manipulating symbols and numerals just as a computer does, he produces appropriate strings of Chinese characters that fool those outside into thinking there is a Chinese speaker in the room.
[Emphasis added.]
Unless those outside are satisfied with a very rudimentary back-and-forth, such a program would have to be amazingly complicated (and those outside very patient, or the operator superhumanly fast). It's not just a question of "look up input Chinese character and return corresponding output character" -- which is never explicitly stated, but which we're subconsciously led to by the image of a human "following the program for manipulating symbols and numerals".
Dennett gives an example where the outside person tells a joke, and asks the room's operator to explain it. You could also imagine a reading comprehension exercise, with questions ranging from purely structural ("What is the third word on the fifth line?") through semantic ("What colour was the girl's dress?") to analytical ("Why do you think the boy was sad?") Questions can be self-referential, or depend on previous questions (and their answers) or on a vast mass of knowledge we take for granted (a dress the colour of snow is white; a small boy might cry if his kite gets stuck in a tree).
It doesn't seem so intuitive that a system that complex lacks anything we might legitimately describe as "understanding".
With such setup (require infinite memory) the system is Turing-complete of course.
If it works as you described it can't even answer "what was my n-th last question".
Briefly (as far as I understand), a lot of philosophical thought has been dedicated to computability, not enough to computational complexity, i.e., the resources needed for computation. A naive "lookup table" implementation of the Chinese room simply wouldn't fit in the Universe. You'd need to throw in a great amount of compression, and then you get something that could possibly be considered "intelligent" (http://en.wikipedia.org/wiki/Hutter_Prize)
You can't prove that. For all possible experiments that can be performed we can construct system that will be indistinguishable from entity we accept as understanding Chinese.
If you got atom-by-atom description of human brain without knowing beforehand what it is you wouldn't be able to reason that this brain understands Chinese, so why do you think you can judge other systems?
> they don't evoke feelings, memories, images in the person in the room,
We were speaking about understanding, not emotions, memories etc. Yes you can define "understanding" = being like me, but it's not fair definition, and would exclude a lot of people.
And then of course you can't proove that there are no emotions and memories. They can be simulated by system as well. Even if you wanted lookup table - you would need to include writable memory so the system can rembmber previous questions when asked about them, at that point the system is self-modifiable and can be thought of as having memories and emotions.
> there is no analysis, no agreement or disagreement with what is being said
How do you know there's no analysis? If the system is complex enough you can't know what it does internaly. Or show me theory of consiousnes that can distinguish systems that can understand Chinese and can't basing on the specification of the system.
Just like the individual neuron in your brain do not understand Chinese so does the person in the room not understand it either. The entire house though does.
Most of the hard problem of consciousness arguments are silly and amount to little more than “a computer has no soul.”
That's where I would disagree. But I'm not fit to give a full explanation here— thinkers such as Hubert Dreyfuss (What Computers Can't Do) do a much better job of explaining the critique (Dreyfuss is working off of Heidegger and other phenomenalist) .