Neuroscientist Kenneth Miller has an interesting post at the New York Times discussing the feasibility of mind uploading:
I am a theoretical neuroscientist. I study models of brain circuits, precisely the sort of models that would be needed to try to reconstruct or emulate a functioning brain from a detailed knowledge of its structure. I don’t in principle see any reason that what I’ve described could not someday, in the very far future, be achieved (though it’s an active field of philosophical debate). But to accomplish this, these future scientists would need to know details of staggering complexity about the brain’s structure, details quite likely far beyond what any method today could preserve in a dead brain.
This fits with what I’ve read from other neuroscientists. It starts with the assumption that the mind is a physical system that exists in this universe, and operates according to the laws of nature. We have good reasons for making this assumption. All of the evidence points toward the mind being entirely in the brain. None of it requires any ghostly aspect of it as an explanation. (Of course, substance dualists will insist that the evidence doesn’t rule it out, which is true, but Occam’s razor does seem to.)
Given this assumption, there doesn’t seem any reason, in principle, that a human mind couldn’t be uploaded, or copied in some other manner. The question is, how likely is it to happen in the near future? Again, Miller gives a response similar to that of most neuroscientists:
Neuroscience is progressing rapidly, but the distance to go in understanding brain function is enormous. It will almost certainly be a very long time before we can hope to preserve a brain in sufficient detail and for sufficient time that some civilization much farther in the future, perhaps thousands or even millions of years from now, might have the technological capacity to “upload” and recreate that individual’s mind.
Although most neuroscientists I’ve read aren’t quite that conservative, seeing it as possible that we might be able to accomplish it in a century or two. Thousands of years, or even millions, seems extremely pessimistic. Of course, predictions about the future are rarely worth the ink their written in (or these days the digital storage they occupy), and if it is possible to achieve it in the near future, it’s unlikely to be accomplished by anyone who has ruled out the possibility.
One thing that Miller doesn’t discuss, is that we’ll likely have to have a thorough understanding of natural minds and how they arise from brains before we can build an artificial one, a general artificial intelligence. Certainly computing power will continue to increase, and systems will become increasingly sophisticated, but I don’t think they’ll achieve a state where we might be tempted to refer to them as a mind, until we understand enough about organic minds to recreate them.
All of which I see as reasons to be skeptical of any kind of hard takeoff singularity event as Kurzweil and similarly minded futurists often predict. Eventually mind uploading or copying may be possible, but it’s likely centuries in the future. And Miller seems to throw cold water on the idea of modern cryonics, having your brain preserved in some manner so that your mind could be uploaded when the technology develops, although I’m sure a cryonics enthusiast would point out that we don’t know enough to categorically say it won’t work.
For me, contemplating mind uploading is like thinking about ways we might use to get to the stars. I have little hope I’ll ever get to do it, but it’s still fun to speculate.