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> which the machine is unable to represent. If you believe that a computer will eventually be able to accurately simulate a human brain, you might as well give

> which the machine is unable to represent. If you believe that a computer will eventually be able to accurately simulate a human brain, you might as well give up right now. Since if a computer with all its constraints is able to simulate a human (brain), but cannot do this, then a human can't do it either. Conversely if a human can do this but a computer can't, then a computer can never simulate a human. Don't tell this to a software developer working on AI. They might quit their job and become a baker instead. I don't think you would have any effect on a mathematician, since they would already be acutely aware some things provably cannot be done.

mjburgess 4y ago
Yes, I don't believe a concrete computer can "simulate" anything in the relevant sense, let alone a human brain. Computer, as defined abstractly, is just any abstract function from {0,1}^N->{0,1}^M. Any realisation of that, eg., by providing each {0,1} as an electrical switch, realises physical properties associated with electrical switches only. The reason that electrical computers are useful has vastly more to do with the electrical part than the computer part. The "computational properties" of the electrical devices we call computers are relatively trivial. But in any case, no system in virute of being an implementation of a discete function thereby acquires physical properties. A woodern "comptuer" is useless precisely because you can't play video games on it. Likewise, even if the brain can be described by a discrete function -- (which is so implausible as to be a bit mad and certainly purely an act of faith) -- then it still requires the relevant physical properties to implement. These properties are extremely unlikely to be those of electrical switches. The "computational work" done by biochemical signalling alone should probably be regarded as "infinite", saying much about the limitations of discrete conceptions of information.

mjburgess 4y ago

Yes, I don't believe a concrete computer can "simulate" anything in the relevant sense, let alone a human brain. Computer, as defined abstractly, is just any abstract function from {0,1}^N->{0,1}^M. Any realisation of that, eg., by providing each {0,1} as an electrical switch, realises physical properties associated with electrical switches only. The reason that electrical computers are useful has vastly more to do with the electrical part than the computer part. The "computational properties" of the electrical devices we call computers are relatively trivial. But in any case, no system in virute of being an implementation of a discete function thereby acquires physical properties. A woodern "comptuer" is useless precisely because you can't play video games on it. Likewise, even if the brain can be described by a discrete function -- (which is so implausible as to be a bit mad and certainly purely an act of faith) -- then it still requires the relevant physical properties to implement. These properties are extremely unlikely to be those of electrical switches. The "computational work" done by biochemical signalling alone should probably be regarded as "infinite", saying much about the limitations of discrete conceptions of information.