This whole point was not about creating a computer that could think like a human brain. It was about a computer powerful enough to simulate every single particle in a universe, with all the forces acting between them.
I know exactly what you mean, and my post above was directed towards exactly what you wrote here: To pull it off convincingly, you'd pretty much have to simulate the entire cosmos.
Just that, obviously, you seem to think it takes LESS performance than simulating "only" a brain. The problem is, you're grossly misjudging the nature of computers. "to compute" is, in another word, "to calculate". A Computer is nothing more than an insanely powerfull calculator.
It can't do anything else but calculate numbers!
Because of this, everything you want to teach to a computer you have to teach him in mathemathical terms. And he needs to calculate every single bit of it. The functions we use in physics are an abstract way to describe what's happening in reality. Gravity doesn't know that it is a product of mass, and it doesn't care. It simply occurs, because that's the way things are. We found ways to calculate how much mass results in how much gravity and at what distance, but that's "only" for our practical usage. Gravity works just as well without doing any calculations.
Gravity in a computer doesn't. Nothing in a computer programm just happens because that's the way it is. Everything that is occuring in a computer programm has been calculated, which needs time.
If you play a game and look at a character, that character does look as it looks to you because the position of every single vertex in it has been calculated based on your position and viewing direction. You could not, for example, look at it from two sides at the same time. That would need another thread on the GPU to calculate the positions of the vertices from another angle, and would need double as much time. (When you're playing an online game with a friend, you have two GPUs at work, one calculating only his view and one calculating only yours).
So, you can't just programm an object "Proton" and an object "electron", throw them together and expect to get atoms or even molecuses back.
Every possible interaction has to be defined by mathematical formulae, and every single step has to be calculated. It's a lot of numbers to crunch. Too many for any possibly imaginable computer, considering we're talking subatomic levels and the whole cosmos here.
I'd suggest that you'd get at least a basic understanding of computer sciences before speculating any further on the topic. The above mentiond "emperors new mind" is a very good start for people like you and me that generally don't have a clue what exactly they're talking about.
The text I'm writing here only exists in a server, but does that make it any less real? If it wasn't, you couldn't read it.
The very fact that I can read it makes it real. A computer has no concept of reality whatsoever, because of the very nature of his purely mathematical logic, he is unable to have any idea of what he is actually doing. You need a way to get a grasp of non-mathematical concepts to develop awareness, because philosophy can't be described mathemathicly. This is why it's so hard to make a good translator: Language is difficult to describe in mathematic terms (not impossible, probably, but difficult). And don't tell me google translator made a lot of progress during the last years. The method of exactly HOW google translator has been improved is pointing away from refined AI towards pure brute force computing relying on a humongous database. Google translator is doing nothing but searching for comparable forms of a sentence on the net and then does a bit of computing to decide which comes up with the highest probability of being aplicable in this case. It doesn't have a clue to what it's actually doing, nor does it have a clue what the stuff it reads actually means. Nor does it care.
Understanding this, you realise that the whole reality of the text you've written is someone who can interprete it and respond to it, which a computer can't (That would be the turing test, by the way). If noone could read what you wrote above, its whole reality would be a few zeroes and ones somewhere on a server indeed. The same aplies to handwriting by the way, which is nothing more than ink sprawled on a paper in funny patterns unless soeone can interpret it. The difference between a stain of ink and a letter is indistinguishable to anyone that doesn't know what a letter is. And a computer doesn't. You can describe to it some forms of letters in mathematical terms, and it can compare those discriptions with what it sees through a scanner and calculate the probability of it aplying to a reference it has in storage. That doesn't mean it can read, because if it happens on a wonderfully ornamented letter that somebody took an hour to draw and any human would recognise instantly if he is familiar with the basic letter, it won't be able to make anything more of it than with the stain of tomato sauce that happened to be on the letter for some reason.