In transhumanism and science fiction, mind transfer (also referred to as mind uploading or mind downloading, depending on one's point of reference), or whole body emulation refers to the hypothetical transfer of a human mind, body, and environment to an artificial substrate.
In the case where it is transferred into a computer, the situation would become a form of artificial intelligence, sometimes called an infomorph. In the case where it is transferred into an artificial body to which its consciousness is confined, it would become a robot, albeit one which might claim ordinary human rights, certainly if the consciousness within were feeling (or were doing a good job of simulating) as if it were the donor (see cyborg).
However, even if uploading is theoretically possible, there is currently no technology capable of recording or describing mind states in the way imagined, and no one knows how much computer power or storage would be needed to simulate the activity of the mind inside a computer.
Uploading, in this sense, is a common theme in science fiction. One of the earlier instances of this theme was in the Roger Zelazny novel Lord of Light. Those with a strongly mechanistic view of human intelligence, e.g. Marvin Minsky, or a strongly positive view of robot-human social integration, e.g. Hans Moravec and Ray Kurzweil have openly speculated about the possibilities and their desirability. The fiction of Greg Egan has explored many of the philosophical, ethical, legal, and identity aspects of mind transfer, as well as the financial and computing aspects (i.e. hardware, software, processing power) of maintaining "copies."
The idea of uploading human consciousness in this manner raises many philosophical questions which people may find interesting and disturbing, such as matters of individuality and the soul. Vitalists would say that uploading was a priori impossible.
Uploading consciousness into bodies created by robotic means is a goal of some in the artificial intelligence community. In the uploading scenario, the physical human brain does not move from its original body into a new robotic shell; rather, the consciousness is assumed to be recorded and/or transferred to a new robotic brain, which generates responses indistinguishable from the original organic brain.
How might mind transfer be performed?
An extremely crude means of moving (if not exactly 'uploading') consciousness using current technology is the head transplant which has been done on primates. Another such crude means which some researchers think is feasible in the near term is the whole-body transplant which moves only the brain. Since it is not easy to tell whether a body contains its original brain, nor necessarily easy to tell whether a body has the head it was born with, some of the identity questions are identical for these methods and those based on robotics. However, these methods do not involve copying the mind nor moving it into a non-organic medium, such as an electronic computer. Accordingly, they are technically quite different, and subject to normal limits of organic bodies and brains.
True mind uploading remains speculation; the technology to perform such a feat is not currently available, nor is it expected to be for several decades at least.
The most likely method we can foresee is serial sectioning, in which the brain tissue and perhaps other parts of the nervous system are frozen solid, sliced apart or ablated layer by layer, and each layer scanned at high resolution, perhaps with a transmission electron microscope. The scans are then recombined and uploaded to appropriate emulation hardware (i.e., an artificial brain). This would require MEMS but would not seem to require molecular nanotechnology.
A more advanced hypothetical technique that would require nanotechnology might involve infiltrating the intact brain with a network of cell-sized machines to "read" the structure and activity of the brain in situ, much like current-day electrode meshes but on a much finer and more sophisticated scale. This might even allow for the replacement of living neurons with artificial neurons one by one while the subject is still conscious, providing a smooth transition from an organic to synthetic brain - potentially significant for those who worry about the loss of personal continuity that other uploading processes may entail.
It might also be possible to use advanced brain imaging technology to build a detailed 3-dimensional model of the brain using non-invasive methods. This may run into physical limitations on the resolution that can be achieved, however. Very high resolution brain imaging (down to the nanometer) is possible but it would require destroying the brain by means of serial sectioning scan describe above.
It has also been suggested (for example, in Greg Egan's "jewelhead" stories) that a detailed examination of the brain itself may not be required, that the brain could be treated as a black box instead and effectively duplicated "for all practical purposes" by merely duplicating how it responds to specific external stimuli. This leads into even deeper philosophical questions of what the "self" is.
Copying vs. moving
By some definitions, the copied consciousness would 'be the same person' as the donor of the consciousness. In that case, this new being -- the same person as the original -- could have all the rights of the consciousness donor, including the disposal of the old body. By other definitions, the two copies would immediately be considered different people and the issue of which copy 'inherits' what can be much more complicated. This problem is similar to that found when considering the possibility of teleportation, where in some proposed methods it is possible to copy (rather than only move) a mind. This is the classic philosophical issue of personal identity.
Philosopher John Locke published "An Essay Concerning Human Understanding" in 1689, in which he proposed the following criterion for personal identity: if you remember thinking something in the past, then you are the same person as he or she who did the thinking. Later philosophers raised various logical snarls, most of them caused by applying Boolean logic, which was the only logic available at the time. It has been proposed that modern fuzzy logic can solve those problems, showing that Locke's basic idea is sound if one treats personal identity as a continuous rather than discrete value.
In that case, when a mind is copied -- whether during mind uploading, or afterwards, or by some other means -- the two copies are initially two instances of the very same person, but over time, they will gradually become different people to an increasing degree.
Ethical issues of mind uploading
The ethical issues of uploading consciousness are difficult even to list. They would involve challenges to the ideas of body identity, human immortality, property rights, capitalism, human intelligence, an afterlife, and man as created in God's image. Often, these challenges cannot be distinguished from those raised by all technologies that extend human technological control over human bodies, e.g. organ transplant. Perhaps the best way to explore such issues is to discover principles applicable to current bioethics problems, and ask what would be permissible if they were applied consistently to a future technology. This points back to the role of science fiction in exploring such problems, as powerfully demonstrated in the 20th century by such works as Brave New World, Nineteen Eighty-Four, Dune and Star Trek, each of which frame current ethical problems in a future environment where those have come to dominate the society.