I have also read
Age of Spiritual Machines and find Mr. Kurzweil's ideas to be interesting. However, I think he underestimates the human tendency to resist change, especially when it concerns one's own body. After all, the majority of people on Earth don't even have tattoos. People have fear and anxiety about even minor surgery. Implants are much more involved. Uploading is unthinkable.
IMHO, 2020 is too soon for such a man-machine merger as Kurzweil fantasizes about. Perhaps, though, that is because I fail to see how a sea-change in human attitudes towards machines will come about in 15 years. I could be wrong, but we'll have to wait and see, won't we?
There are, of course, dangers with the technologies Kurzweil describes. Computer viruses are only the beginning. I think that virtual reality, once it becomes realistic enough, will become an addiction for many people, perhaps even millions. The ability to extend not only life but also
youth indefinitely will cause a lot of psychological adjustments, at first between those who undergo the treatment and those who do not (there will be plenty of the latter, I assure you). I predict that boredom will be the biggest social problem of the late 21st century. Many of the "chronically young" will go insane and eventually commit suicide, either through peaceful (euthanasia) or violent means (ever-increasing thrillseeking). Those among us today who are the most prone to tinkering with things, trying to figure things out, and creating new things may be the ones most likely to survive (i.e. will be the least bored) in the future. Ultimately, we seem to be heading for a "society of mind" -- a species of scientists. Whether that's a good thing or not is up to You.
- Rob