Imagine a learning system made of gigantic networks trained with everything mankind wrote. A machine that tries to detach itself so as to allow our global unconscious making random associations and a suspension of disbelief. What would we have?
Old dirty Picasso said - computers are useless because they only give answers. As our little egghead would be running on a computer, would it also still be useless?
If you avoided the fatal meaning-overload induce by playing with words, this kind of machine would allow you to comprehend everything one could say. Based on the Verb chronology, it would be able to get the fittest linguistic pattern out of the entire history of Scripture.
Even all the questions a normal being from our actual time could ask would be ready to be asked. Nobody can really imagine how clever such a system would look. Imagine someone who can automatically predict what you're going to say based on what he told you, who can surf instantly upon the sum of mankind's knowledge. This entity would easily be able to ask you relevant questions and would prettily fit in most of the intelligence requirement specifications. Isn't intelligence simply an answer, if we know the right question?
Ok, that's it, we got our best cognitive system. Bravo! You created the Ultimate Rhetoric Warrior.

But is it so much better than a single human brain? Is it so much useful? Could we already start to dirt our pants and find ourselves a new planet where science will be forbidden?
No. Not yet. This speech gladiator would be easily thrown to the ground by any children's mischievousness.
Why?
First of all, after spending enough time with this machine, kid's brain would easily seize the best out of it. He will cream off this gems cavern to grab the best emergent diamond. After few years the kid's biological network would easily tame this new toy and use it to showoff during playtime.
Secondly, the older your get the closer your get to this monster of narration. The more specialized you get, the less creativity you can squeeze out of yourself. You can faint it with brilliance. You can become a specialist of illusions and pretend your creativity is rejuvenating. You'll just become one of those quacks who claim they can keep human body up forever. There are some ways to balance the decay effect, but come one, this peddler's trick is too famous to be anything else than a rip-off.
Creativity fades in the old age and that's precisely what makes mankind so useful. That's where kid's superiority lies and where machines bite the dust.
This hiding doesn't prove cognitive network is a wrong approach, it only emphasis the irrelevancy of my system's specifications.
Here we have a very interesting concept to hands, but still not as much as a single chemical brain. If my description is seducing and feasible, it definitely doesn't conduce to transvaluation.
If Neural Network approach can physically reproduce what's our brains do, there is still an important lack of questioning. Are we really willing and ready to grin and bear it? We'll probably have a better picture after meditating about our future duels with those Ultimate Rhetoric Warriors.
Or maybe we'll evolve so much we won't even notice they already exist.
Unless they fail we wouldn't be able to question their utility anymore.