The first thing that came to mind when I read this scenario concerning Vern’s Volvo being slowly taken apart and replaced piece by piece is the story of Anakin Skywalker/Darth Vader. Physically, almost every part that was once Anakin has been discarded and replaced with the mechanical components of Darth Vader. But as we see at the end of Episode VI when “Darth Vader” saves his son Luke, the emotional entity of Anakin has always been there, simply buried under a physical monstrosity who was put under a lot of emotional stress in his younger years. Even though Vern’s current Volvo is in no way a physical monstrosity, I think the same rules apply.
The car may have been replaced bit by bit over the course of twenty years, but the intrinsic value of the car for Vern has always remained. The idea of the Volvo being Vern’s is what really matters. From Vern’s perspective, the car is something that he’s been through a lot with. If you have a car for twenty years, chances are good that you will grow attached to it. Vern’s attachment to the car is surely what drove him to repair it so many times in the first place. He made a conscious effort to keep his car in working order because it has that innate value to him. Telling Vern that his real Volvo is the hunk of parts sitting in Grace’s garage would probably offend him. In fact, the process of repair and replacement that the car has been through adds to the intrinsic value of the car.
If Grace were to take all of the parts that she collected during the years of repair she did for Vern’s Volvo and create a functioning vehicle from it, that car could not be considered Vern’s. It would only be a sum of parts collected over time. Vern did not experience any part of his life with that particular form of the car. The repaired form of the car that he currently owns is the only one that could actually be considered his. This is because in those twenty years of ownership, even though he made the conscious effort to repair and replace what is necessary, he always held on to the same idea of the car, which has innate value to him. This once again leads me to the comparison between the Volvo and Anakin Skywalker. Even though Darth Vader was replaced part by part thanks to his scars from various egregious deeds, the emotionally troubled but true Anakin Skywalker has always been under the surface. If someone found all the “spare parts” of Anakin Skywalker (which would be rather disturbing) and reanimated some sort of separate version of him, it would not be Anakin because no one could recreate the emotional journey, from cocky pod-racing kid to fratricidal emotional wreck, and make it a part of the reanimated Anakin.
Consider even the history of humanity applied to this logic. People born, live, and eventually die. The people that are around today are a completely separate group of individuals from the people that were around hundreds of years ago, but we are still considered the collective of humanity. Even though each individual has died and been “replaced” it is our history which makes us humanity, which is an idea that has stuck with us since the rise of civilization. No one would ever dare to rename “humanity” simply based on the logic that we are not the same group of individuals that we were a few centuries ago.
The last thing I have to get off my chest is that, from a scientific perspective (which I know that not everybody finds fascinating, but I am obliged as a “science person” to point out), our physical entities are not the same physical entities that we remember from years ago. Atoms and molecules move from place to place and are constantly replacing each other. For example, other water molecules have replaced the water molecules that composed the majority of our bodies as children. That same rule applies to the other atoms and molecules in our bodies. We may each be a constantly changing set of matter, but we still consider ourselves the same people that we were when we were younger. This is because we hold the idea of ourselves as near and dear. Vern’s car may have been reconstructed into a different physical entity over time, but Vern’s concept of his car over time has remained constant and near and dear to Vern.