With a new Terminator movie in the theaters, essays on machine intelligence are popping up all over. I think we are still a long, long way from computers that have a human-like intelligence. So far, Artificial Intelligence has been a colossal failure, although we have certainly learned a lot about ourselves in the process. Example: until we tried to program computers to do it, philosophers had never even considered what we now call the "framing problem." When we face a problem, how do we know what set of our memories and thought routines to consult in answering it? We obviously can't review the problem in the light of everything we know, but how do we go about defining what we should consider? It is, it turns out, a very hard problem, and it is one of many, many problems we have to solve before we can make a machine that thinks like we do.
That being said, it seems to me that it is only a matter of time before we create machines that can do a lot of the things we do. I am usually skeptical of using science fiction as a guide to what really might happen, but I think that limits on the development or construction of intelligent computers might well be on the horizon. This could well be one of the most important political questions fifty years from now. Another possibility is that instead of considering machines as rivals, we will use them to augment ourselves, wiring extra memory capacity and calculation power into our own. This, however, might lead to further political battles, since with such additions the rich might become much smarter than the poor.
So I see many unknowns in the future of our relationship with computers. But there is one thing I feel quite certain about: we will never be able to download our personalities into computers and live extended digital lives. This is just a high tech version of the old dream of immortality. We are biological entities, rooted in our bodies. We might be able to create some digital simulacrum of ourselves that would be something like us, but it would not be us. How we think and feel is a product of our bodies. We feel different after exercising, to take a simple example. Who we are is also defined as much as anything else, by our mortality. Without bodies that can get sick and suffer pain and die, we would not be ourselves. We would be something other than human.
To be human is to live on a trajectory from life to death, in a body made of flesh and bone. Anything else is an illusion.