Interestingly, it may be that Heisenberg uncertainly requires that if you extract all of the information out of Riker in order to reform him, you must necessarily destroy the original Riker, saving you a bullet. (IANAP, _obviously_).
If it turns out that the thing critical to our being is deep within our neurons, and that the computations that take place are similar to quantum computing and rely on sub-atomic processes, and that the rest of the body (among other things) keeps its environment stable enough to "keep state," then the machine needed to copy the mind would end up destroying the original. Or, if it doesn't read atomic information at that level of detail, the "copy" will have a similar infrastructure but will instantly be divergent from the original because the "current" thoughts of the original will not have copied.
I mean, putting aside philosophy and actually getting down to the brass tacks so we can start building this machine. (:
Sorry, but [citation needed]. Penrose, for one, thinks details on that scale are the essence of you.
Besides, that's just trying to explain qualia. Pretty sure no one thinks memories are quantum phenomena.