Considering this week's episode of Stargate Atlantis I thought it would be appropriate to talk about one of the... strangest ideas of Transhumanism, Mind Uploading. Mind Uploading is the transference or copying of one's consciousness into a body other than that of the original, usually a computer or clone.
One might wonder why someone would give up their original body and become a machine, there are several reasons why. The most obvious of those is the near immortality allowed by having a body made of metal instead of flesh and bone plus being able to easily copy oneself in order to make backups or a distributed network brain, in addition the human brain only has enough available memory for maybe four centuries, while a computer can always have more memory added as needed. Also a computer program doesn't need any physical resources other than space to house the machine and electricity, anything else would be provided by a virtual reality. Finally an uploaded personality would be able to travel at the speed of light through data transmissions and experience life thousands of times faster than a humans.
There are several possible ways of Uploading memories, all of which are highly theoretical, and most of which involve copying the brain's structure and data (just to be clear, when information is uploaded or downloaded it's being copied, not really transferred). One such method would be to freeze the brain and cut it into "serial sections" to be scanned by an electron microscope so that the neural net may be recreated. Fortunately it may also be possible to use a highly advanced MRI or nanomachines to just read the information in a living brain without destroying it, of course this means that if the original was still alive then he/she would have a digital clone with the exact same memories and personality up to a certain point. These methods rely on pattern identity theory which assumes that if one has the same memories as a previously existing entity, then he/she is the same person.
Personally I think that if my brain was scanned and my neural network and memories recreated in a computer it would just be an AI that thought it was me and if my brain was taken apart and destroyed all at once then my personal perspective would end and I would die. However, there are two other hypothesized methods that would enable one to become a machine while retaining personal perspective. The first, and perhaps the most technologically feasible method of Uploading is cyborging, as parts of the brain are mapped and analyzed they are replaced with implants that mimic the functions of the replace parts, this method would take months or years to complete but the individual would retain their perspective during the process. The other method involves the use of nanomachines to replace the individual neurons in the brain one by one with artificial substitutes. If the technology becomes available in my lifetime I will probably have cybernetic enhancements done to my body if not my brain, but I would prefer to retain as many biological parts as possible for as long as possible. Maybe in a thousand years I will be distributed across several computer nodes and biological bodies scattered throughout the solar system.