A mindclone is a software version of your mind. He or she is all of your thoughts, recollections, feelings, beliefs, attitudes and values, and is experiencing reality from the standpoint of whatever machine their mindware is running on. Mindclones are mindfiles being used and updated by mindware that has been set to be a functionally equivalent replica of one’s mind. A mindclone is your software-based alter ego, doppelganger, or mental twin. If your body died, but you had a mindclone, you would not feel that you personally died, although the body would be missed more sorely than amputees miss their limbs .

We have absolutely no experience with mindclones. Never in history has there been anything like them. Hence, it is natural to find it difficult to understand the concept. From time immemorial we have thought of our identity as being limited to one instantiation, namely that contained within our body. To grasp mindcloning it is necessary to envision identity as being a unique pattern of thinking that can occur in two or more substrates or forms. If you can accept that a mind can be duplicated, with appropriate mindware and a rich enough mindfile, then you have accepted that a single identity can occur at least twice.
Now, it is certainly true that an easy distinction can be drawn between an original identity and that of its mindclone. Simply by virtue of being a copy, the mindclone is not the original, and hence it can be said that the mindclone does not have the same identity as the original. Yet, this is a distinction without significance. It is analogous to claiming that identity changes over time because people grow and acquire new experiences. While there is no doubt that our personality evolves, and our thoughts change, we are still the same person – the same identity.
So, why is it that we feel an uploaded version of our mind knows that it is an upload, and is thus not really us, whereas an aging version of our mind knows it is different from its youth, but is still definitely us? The reason is our deep-felt bias, based upon our entire human experience, that identity is substrate-specific. Some people take this so far as to believe that transplant recipients, especially of hearts, assume some of the identity of the organ donor.
With mindcloning we will have our first experience with the technological possibility of substrate-independent identity. It will take some time for society to adapt. Ultimately, though, most people will understand that just as a person’s voice can be in two places simultaneously via telephone, their identity can be in two places simultaneously via mindcloning.