When it comes to phantom pain, could it not be explained by the idea that the ‘feeling’ is all going on in your head and is generally the brain interpreting the signals it receives from your hand? If you lose a part of your body, the connections on the brain end are still there and are just cut off further down, so your brain may still assign feelings to no longer existing parts of what on its end is a complete body. You can also still send the signals down to where the arm would be, because it’s a hardware rather than a software problem.
