Why would that be, if the new prosthetics are identical to their original limb? How could they even tell the difference?
I didn't say that they were
identical. I said that they were
functionally indistinguishable. Especially to someone who doesn't know it's there.
Time. I've said it before. If it takes more time than the Universe will exist to make something, it cannot be made. You are appealing to magic at least as much as any magic bean theory when you suggest that some future technology is going to make all the problems disappear.
The word "if" is doing a lot of heavy lifting in that argument. Given the hypothetical situation of infinite time, a sufficiently advanced device
could simulate a human brain. There would be nothing else to prevent it.
And, again, it is silly to ask what is to prevent us from replicating the human brain when we don't know the composition, function or means of operation of the human brain.
We do know the composition, function and means of operation of the human brain. We know what it's made of, what all the subparts of the brain does, what happens when you knock them out, and a whole lot more that you are not giving modern science credit for.
Your persistent demand that I tell you what specific mechanism prevents our replicating a human brain is silly and childishly naive.
Now you're getting desperate.
What little we know about the human brain is that nothing can replicate it but the natural manner of human reproduction. As I mentioned, the human brain is the most complex structure known in the Universe. That means, nothing we know of has made anything else as complex as it is, functional or not. That greatly lowers that odds that anything could make a functioning brain like a human brain.
But there is no reason
in principle that such a ridiculously complex structure
could be replicated.
I suppose you have one of those in your back pocket.
Of course not. But if one did exist, don't you think it would be easily capable of such a feat?
We know of 3000 types of neuron and glial cells. You tell me what each type does, because nobody else knows.
Researchers only recently discovered that the timing of stimuli is critical to how they are processed by the brain.
The only functions of the brain that have been known for decades are the broadest strokes, and even that is only crudely known. If you think it is so easy, feel free to make one to bring to class!
Again, you are giving very little credit to modern neurological science here. Sure, there are things we still don't know. There are things that
I certainly don't know, because I'm not a research neurologist with thirty years of practice under my belt and dozens of published papers. But, I'm willing to bet, neither are you. Your demand that
I tell you everything about the brain is hollow and you know it.
Yes, there are still things we don't know about
precisely how certain parts of the brain operate to produce the results that we observe. These are extremely fine details, and incredibly hard problems. But the amount we
do know fills volumes! Shelves! Libraries! And there is no reason to believe - no reason at all - that we as a species will not one day understand everything there is to know.
And there is no reason to believe -
no reason at all - that once we do know all of it, our technology will not one day be capable of simulating it.
And do you know why I hold this view so strongly? Because the only alternative is Cartesian dualism. The mystical idea that the mind is somehow separated from the brain. that it exists through some magical ineffable process that has nothing to do with the operation of the brain, that the mental exists independent of the physical and the physical can't think. And this is both profoundly unscientific, and completely falsified by everything we know about what happens to the mind when the brain gets damaged.
But all of the above is actually completely irrelevant because nobody has yet proven that the
only way to simulate a mind is to copy precisely the physical form and operation of a biological brain. There might be other ways of achieving a
functionally indistinguishable result. We just don't know yet. But it can't be absolutely ruled out.