When the doctor learns that his creator, Dr. Zimmerman is terminally ill and the best doctors and experts have been unable to cure him, he has his program transferred to Jupiter Station via the Pathfinder Project's communications link. There, however, he meets an all too bad-tempered Dr. Zimmerman, who has not only given up all hope, but also sees his creation - the doctor - as old-fashioned and outdated. After all, there is now a far superior EMH with the Mk IV model.
Robert Picardo is excellent again in this episode. Especially because he can be seen in a dual role and plays two quite different characters. The conflict between both characters is also extremely moving and all too understandable. While Zimmerman is like a father figure to the doctor, at least something that comes closest to "family", to Zimmerman the doctor is an eternal reminder of failure. A disappointment. An invention that earned him only scorn and ridicule. The first EMH model that he created in his own image has long since been retired from Starfleet and is now eking out an existence in waste disposal. When Zimmerman looks at the doctor, he is looking into a mirror that is once again rubbing his failure in his face.
This episode has a profound message: While Zimmerman judges his creation solely based on the abilities programmed into it and does not initially see it as an individual, the doctor tries to convince him that he is now more than the sum of his algorithms. He has outgrown his original programming. The spark of creativity and individuality ignited in him the desire to be more than just a projection of light. Basically, it is the old question of when a machine, a robot, when AI ultimately becomes an independent, sentient living being that is aware of itself and its environment and leaves the limits of its own programming in order to truly develop freely.
