It may very well be the case that this is either true or false. We simply don't have enough evidence.
And given the fact that we are discovering new properties of matter and organic reactions all the time, there is a bias towards this being false.
From the biological point of view, the simplest species is AS SUCCESSFUL as the most complex species, since both are still alive and procreating.
Why do humans have eternal significance? To whom?
Known to who? I don't like this very self-referencing way of thinking. Very similar to the discovery of America... people were already in America way before Columbus came and "discovered" it. (although apparently he didn't even realize he hadn't arrived to India)
He/She's allowed to have such an opinion, but this discussion is trying for a particular feel and that isn't contributing helpfully to it.
The poster you are responding did not claim that humans are the shit. They merely pointed out the fact that we have so far proven incapable of proving that we aren`t said shit. Now, you could argue that such a hypothesis could only be falsified by the construction of a machine consciousness. That, however, is orthogonal to the fact that it remains possible that there is in fact some bizarre quality of the universe or the human race that makes machine consciousness impossible. Not a terribly scientific position to take, perhaps, but a perfectly sound philosophical one.
No, human intelligence is an emergent quality, and I fathom that even our massive representations of humanity's information (akin to what Google is compiling) will soon begin to exhibit interesting qualities of its own once it becomes complex enough to exhibit perhaps interesting, unanticipated emergent qualities (in fact, if it didn't I would be absolutely shocked). Many strange and unpredictable (or at the very least unanticipated) things arise from even the simplest of "complex systems" (Conway's game of life and some of Wolfram's automata), much less the wonderful systems detailed by our individual neural mappings and our individual genomes. (q.v. http://en.wikipedia.org/wiki/Emergent_behavior)
People always think that some human will "write" an AI like HAL or the like, but it is much more likely that nature will roll its own AI once we have made a comfy enough nest for it to germinate. After all, isn't that how we got here? (from an evolutionary biologists standpoint anyhow...)
And again, sorry for being contentious. I just despise the "religious" argument (even if there is no "named religion" being expounded... Let's keep Ockham's Razor at the ready here....)
We're machines. That we may not have made a machine of the same class ourselves is an implementation detail. Maybe a large one, but still not really an argument against making conscious intelligent machines. Biology can do it, sooner or later so can we.
Perhaps the disagreement is about when do machines (keeping in mind they're mechanical by definition) cross over to becoming more and more like biological entities (replication). And once they do, is it still coherent to think of them as machines as we use the term today. Or would we then think machines have been elevated to the biological level.
The human has a hideous complicated algorithm in there, involving a live-long history, internal feedback and reflection and arbitrary side constraints.
A spider for example is much simpler. 'If the net shakes, walk where it shakes and eat.' (Certainly, + a batch of regulations to be able to walk and sense, but the point stands).
However, imo at a certain point, a computer program passes the complexity of, say, a spider. Just consider modern compilers. These things are of baffling complexity and do things inside no human can imagine in details :) Or, imagine data mining software, or even just very complicated, security aware network guards. All of these softwares are very, very complicated in their input-output-behaviour, and even though they are not as complicated as a human, they certainly can compete with a spider, at least for me.
And exactly this view is what caused some pretty nasty discussions for me, since some people are just not crossing the line of 'everything is an input-output device of different forms' and they stand hard on the ground that machines and animals are different, because they are machines and animals (and some go ridiculous ways, 'god made animals, humans made machines', and whatsoever, not even some 'but the spider might be more complicated than FOO, because, which whould be a nice discussion :) ).
So, overall, I, as a person who is working hard on being a tolerant, non-racist person (which is really hard), don't see a reason to exclude the possibility of machines and robots being conscious, just because 'they are electrical and not organic' (which has a ring of "he is black, he CANNOT do science" to me. Sorry if I just offended a lot of people).
"Consciousness is not computable" just means we need to build a new class of machine. Whether it's a blob of organic jelly in a box, or an IC with currently unknown structures on it to exploit certain handwavy quantum processes, or whatever; it just makes the task more complex, it doesn't make it impossible.
It may very well be the case that this is either true or false. We simply don't have enough evidence.
It's true, we can't prove it one way or the other at the moment, but that usually just means that Occam's razor should guide our speculations and assumptions. Since the brain seems like all it's doing is performing some computations, why would we ever assume that its true function is to do something more than that?
And given the fact that we are discovering new properties of matter and organic reactions all the time, there is a bias towards this being false.
There's a good chance that the way the brain achieves its computations is indeed a bit more complex than, for instance, an artificial neural network, absolutely. But that's an implementation detail, and there's certainly no reason to assume that there's no computational model that can account for it - biologists are very close to having full working models of individual neurons already. Further, it's highly likely that the brain does its job in a biologically convenient way, not a logically convenient one, and I'd give good odds that there are a lot of logical simplifications that could be made to end up with a cleaner architecture that performs the exact same tasks.
The only two physical process that we know of that are fundamentally impossible to compute with our computing model are quantum computations and chaotic systems. And for chaotic systems we most certainly can simulate them in a way that the output has all the correct properties as far as we know. It's more that we can't reliably do prediction in such systems due to finite precision.
The simple fact is that computers are already our superiors on many tasks. And those tasks are not simple either.