Despite being perceived as an extreme optimist, Kurzweil is the first to admit that this technology could very quickly bring an end to the world as we know it. Stuff like gray goo is a concern, but a biological terrorist attack could happen tomorrow that is based on the very same type of technology he touts as the harbingers of the unimaginable future. He believes we'll exist in a permanent virtual/"real"-reality hybrid. It makes us think about future people spending all day auto-mastubrating to polygons with the genital equivalent of the Power Glove. But we're sick like that, and if Ray is right unenlightened pigs like us won't be around in 40 years. Everyone will be hyper-intelligent, shapeshifting nonbiological humans who can live forever. It's a bummer, a blessing, and a mind-fuck all at the same time. That's about as much as we can explain on our own. Unless you're really religious or dumb, watch on to have your brain melted.