Gatefan1976
Well Known GateFan
The Doctor at least is a computer program. So long as there is a computer on the receiving end with sufficient processor, memory, a compatible basic operating system and holo emitters he can function. His memories after all are just stored code in his program. And Voyager was pretty good about respecting those parameters.
Then you face the option of considering that the brain/mind is a dualistic system and functions like a computer in order to even get to the point of a positronic or photonic brain as displayed by either Data or the Doctor respectively.
OR you cannot have such a system in the first place because consciousness is a function of emergent properties of the biological brain.
Pick your poison