with all this questioning as if a machine can be alive, I had to think, arn't we all machines? isn't a muscle a motor and bone a support? isn't the brain a kind of supercomputer (even though we're far from figuring out exactly how it works)? arn't we just self-supplying machines that are part of yet another machine, the planet?! just add sunlight, a little cosmic dust here and here and, holy crud! after a few billion years, mechanized bi-peds possesing supercomputers are existing! In my opinion, the only difference between our "machines" (or bodies) and the machines we currently make is that our bodies are obviously capable of possesing our consciousness, and our machines are not. Why? Think about it, we can do almost anything we want, think anything we can, all within our body's physical limits and mental experiences. Our most complex machines, robots, can't. They are so much without freedom that they're not even slaves (like the matrix or whatever), they're just tools. They do exactly what we tell them whether it's a good idea or not. The do not explore, forage, or do anything ON THEIR OWN ACCORD. Animals do; a cat will explore a neighborhood, a rodent will hunt down garbage, they'll do all that on their own thought, what little they have. Our robots that make cars, do not do so on their own accord, they do it according to some guy sitting at a terminal telling them exactly what to do.
But could we ever make a machine that's "alive"? After all, that's what we are! This won't happen untill we can make a computer system that is capable of THINKING ON ITS OWN. This would mean this system would have to take in outside information, run it through a processor, and act on it with absolutely no internal human intervention. We couldn't do what we do now when a computer doesn't work right: go in manually and fix a line of code or replace a circuit board. And also, this processor would have to be able to program itself, what we humans call learning. Of course, we don't learn or anything if we don't breath, have a heartbeat, regulate body temperature, or eat starting at the time of our birth. We obviously have some pre-programmed information to keep us going long enough for us to learn about the world and survive in it. A robot that is "alive" would have to have some of this kind of pre-programming to kick-start it's "life". And because this robot would communicate to humans through input and output, it would be unlikely that we could easily control this complex processor that's designed to simply control itself, so in otherwords, we would have to treat this robot as a seperate entity, or another person. This would mean that we humans would be treating it like a learning human, and hey, it'd sure as hell seem alive, right? Just another machine that can think for itself! I think that's when a robot could be considered alive.