In addition to all of this, scientists combining the disciplines of biology and artificial intelligence are developing technology that could one day replace whole human systems (like digestion) with improved biological/machine hybrids. The notion that human and machine are different spheres may change as we increasingly inject machines into our bodies and manipulate our cells. We may even be able to enhance intelligence. Work on gene therapy may yield the ability to turn gene expressions on and off -- which could affect everything from genetic diseases to the aging process itself.
Kurzweil may be a little crazy -- at one point he predicts human life spans of up to 5,000 years -- but let's assume that he's onto something. Let's stipulate that for those wealthy enough to take advantage of it (i.e., most Americans), science will make it possible for people -- say, your children and mine -- to live 200 years.
What would that mean? Let's see, Social Security benefits for 135 years? Medicare for the same period? Prescription nanobots for a century? Assuming that people will remain healthy and working for decades and decades (which is what the futurists predict), would the economy expand due to the continued productivity of well-trained people, or sink under the weight of the extra elderly? (Not all of those doddering around at the age of 140 are going to be on the tennis courts.)
The entire concept of family life would have to change. What would happen to the already high divorce rate if people had to spend the better part of two centuries together? How about military service? Would young men and women who could otherwise expect to live to such astounding ages be willing to risk dying at 20 or 25?
Worth pondering. Of course, if al Qaeda gets the bomb, all bets are off.