This is a fascinating question that is truly asking about the continuity of the self. The teletransporter option essentially creates a clone of oneself, but will the clone be the same? Will the original person die for the replica to replace them? Does the presence of all the memories mean that this replica is the same person?
To answer this hypothetical, I raise another question. If one were to wake up tomorrow with their memories erased and replaced with, for example, the memories of Descartes, and the individual fully believes that they are Descartes, is this person still themself or now Descartes, or a new person entirely?
If the person is still themself, then it might follow that it is not memories that form the continuity of the individual, but the physical body. In this case, if the original body from the space mission scenario is destroyed and remade with new materials, the replica cannot be the original self.
If the person is now Descartes, then it might follow that it is not the physical body that forms the continuity of the individual, but the memories. In this case, if the replica on Mars has the memories and personal identity of the original, the replica can be the original self.
In my opinion, identity is truly based on first, the identity that one places on oneself, and second, the identity that others place on the individual.
In the hypothetical with the individual of replaced memories now identifying as Descartes, I believe that this person is Descartes because they wholly identify themself as Descartes.
This also raises the story of the Ship of Theseus, where if a ship was slowly replaced by other parts until its original parts were all replaced, is it still the original ship? In this case, I believe that the identity of the ship is the identity that others place on it because a ship is not able to form an identity for itself.
Going back to the original scenario of the martian clone, I would choose the teletransporter. The replica on Mars would identify as me, which would mean that I would survive, perhaps not with the same physical components, but with the same identity formed with the same memories. Furthermore, the others around me would also identify me as me, which would support my self-identity. Thus, the choice of a 100% risk-free teletransport would have a higher chance of keeping myself in existence rather than the 50% risk of space travel. The “death” of my original body does not constitute the death of myself, but rather the death of my memories.
The second scenario closely relates to my argument in the first scenario, even aligning more closely with the Ship of Theseus. If parts of my body were slowly replaced, am I still myself?
If I let myself succumb to the virus, my character and memories would be lost. One can argue that even normally, individuals constantly change their character and lose their memories. However, the constant is the identity of the self. Individuals, though ever changing, continue to identify themselves as the same “person,” and this self-identity in itself is the constant. With the virus, not only will my character change, but my self-identification will as well. I will ultimately identify myself as a different person, even though I have the same physical body. Here, there will not be a death of the body, but the death of the self.
If I accept the silicon brain replacements, the physical body is changing, but my self-identity remains the same. Here, I can even argue that our physical body constantly changes, that we are physically much different from as a child to now, that our brain has developed and changed shape. However, this self-identity remained constant during this period of physical change, and will continue to remain the same with the silicon transplants. As a result, I choose the silicon transplants so that I keep the constant of my self-identity.
These are interesting questions and were very fun to answer!
