Before I ask these questions, I'd like to say that my computer knowledge is limited to "if it's not working, turn it off and turn it on again" and the math I intuitively grasp is at roughly a middle-school level, except for statistics, which I'm pretty talented at. So, uh... don't assume I know anything, okay? :)

How do we know that an artificial intelligence is even possible? I understand that, in theory, assuming that consciousness is completely naturalistic (which seems reasonable), it should be possible to make a computer do the things neurons do to be conscious and thus be conscious. But neurons work differently than computers do: how do we know that it won't take an unfeasibly high amount of computer-form computing power to do what brain-form computing power does?

I've seen some mentions of an AI "bootstrapping" itself up to super-intelligence. What does that mean, exactly? Something about altering its own source code, right? How does it know what bits to change to make itself more intelligent? (I get the feeling this is a tremendously stupid question, along the lines of "if people evolved from apes then why are there still apes?")

Finally, why is SIAI the best place for artificial intelligence? What exactly is it doing differently than other places trying to develop AI? Certainly the emphasis on Friendliness is important, but is that the only unique thing they're doing?