I believe that a simulation of a human can be just as conscious as a real human. This is because a real human is merely a complex physical reaction. Despite the laws of thermodynamics, matter has a fundamental tendancy to organize: planets forming from dust, life arising from a pond of chemicals, brains evolving from a world of organisms. Even science itself is another level of organization (the human brain attempting to organize everything it sees).
Of course one has to model the chemical reaction with sufficient detail (far more detail than the neuron level). Physical processes are messy, mushy, complicated, and analog... not the sort of thing for a computer. But, we don't have to model the quantum life of every quark. At some level (perhaps a very low level), the physical processes in the brain can be approximated with sufficient detail to allow thought. Given the incessant human ingenuity with our digital devices, it seems plausable that within the next 100 years we should have the necessary computational power.
I personally find this quite exciting. Certainly life would be different and the simulation would have many imperfections, but it would be better than death (at least given my physical organization-based belief system). I want to live as long as possible, simply because I believe the future will be wonderful. I would give anything to see where humanity is in 200, 1000, 5000 years. I suspect it will be beautiful and amazing.
As many people have pointed out, the problem is the issue of capturing the detail of the human brain. Our neurological understanding of human vision (one area in which I have some experience) is very limited, and the human vision system is probably much simpler than the rest of the human brain. We are much better at adding MHz to our computers than we are at understanding complex biological systems, so I think we will have the ability to do a brute-force physical simulation of the brain, long before we understand the brain.
While I do think we will soon (in the next 100 years) have the processing power to run systems that are just as conscious as the human brain, I don't think we will actually be able to do it, due to an inability to capture the detail of the brain (we won't have brain scanning nanobots in 2029). However, someday, our technological ingenuity will overcome that issue as well.
One potential solution is to have all keyboard/joystick/etc. input be sent to all the other clients before any of it is handled. (This is like the client/server solution mentioned earlier, but treats everyone as servers.) As long as all the user input is applied synchronously at each client, and each client has the same set of deterministic rules, the game will proceed consistently. If anyone cheats (in any way that causes a change in the actions/properties of the objects in the game) then the game will lose consistency. To check this, simply have each client checksum their data every once in a while. If someone has a bad checksum, throw them out of the game (by a vote of the clients). If someone fakes a checksum, then they can continue playing, but they won't be seeing the same game everyone else is. One advantage of this method is that it does allow modification of the game source, as long as everyone uses the same set of modifications.
There is one game that attempts to use this mechanism (here), but it is incomplete (mostly graphics issues currently). I'm not sure that this approach is viable in practice, but I think it works in well in theory.
Slashdot Mirror
I believe that a simulation of a human can be just as conscious as a real human. This is because a real human is merely a complex physical reaction. Despite the laws of thermodynamics, matter has a fundamental tendancy to organize: planets forming from dust, life arising from a pond of chemicals, brains evolving from a world of organisms. Even science itself is another level of organization (the human brain attempting to organize everything it sees).
Of course one has to model the chemical reaction with sufficient detail (far more detail than the neuron level). Physical processes are messy, mushy, complicated, and analog... not the sort of thing for a computer. But, we don't have to model the quantum life of every quark. At some level (perhaps a very low level), the physical processes in the brain can be approximated with sufficient detail to allow thought. Given the incessant human ingenuity with our digital devices, it seems plausable that within the next 100 years we should have the necessary computational power.
I personally find this quite exciting. Certainly life would be different and the simulation would have many imperfections, but it would be better than death (at least given my physical organization-based belief system). I want to live as long as possible, simply because I believe the future will be wonderful. I would give anything to see where humanity is in 200, 1000, 5000 years. I suspect it will be beautiful and amazing.
As many people have pointed out, the problem is the issue of capturing the detail of the human brain. Our neurological understanding of human vision (one area in which I have some experience) is very limited, and the human vision system is probably much simpler than the rest of the human brain. We are much better at adding MHz to our computers than we are at understanding complex biological systems, so I think we will have the ability to do a brute-force physical simulation of the brain, long before we understand the brain.
While I do think we will soon (in the next 100 years) have the processing power to run systems that are just as conscious as the human brain, I don't think we will actually be able to do it, due to an inability to capture the detail of the brain (we won't have brain scanning nanobots in 2029). However, someday, our technological ingenuity will overcome that issue as well.
One potential solution is to have all keyboard/joystick/etc. input be sent to all the other clients before any of it is handled. (This is like the client/server solution mentioned earlier, but treats everyone as servers.) As long as all the user input is applied synchronously at each client, and each client has the same set of deterministic rules, the game will proceed consistently. If anyone cheats (in any way that causes a change in the actions/properties of the objects in the game) then the game will lose consistency. To check this, simply have each client checksum their data every once in a while. If someone has a bad checksum, throw them out of the game (by a vote of the clients). If someone fakes a checksum, then they can continue playing, but they won't be seeing the same game everyone else is. One advantage of this method is that it does allow modification of the game source, as long as everyone uses the same set of modifications.
There is one game that attempts to use this mechanism (here), but it is incomplete (mostly graphics issues currently). I'm not sure that this approach is viable in practice, but I think it works in well in theory.