I found this book extraordinarily provocative, which is why I reviewed it at length. It seems like there will be some kind of symbiosis of computing and brain, even if not a "merging." If in fact there were a merging of human biology and computing, at the level Kurzweil projects, would this change the nature of man at the metaphysical level--or be just another tool to extend human capabilities? If computing capacity were integrated with our brain and, as Kurzweil suggests, increased human intelligence thousands-fold, then, yes, I think we might a new metaphysical nature. Combined with the infinite extension of human life, for which Kurweil makes a detailed argument, there would be implications for fundamental aspects of ethics. So much for the technology. But then Kurzweil rather blithely says, "To manage the implications, we would need rational governance. Oh dear!