A hopelessly hypothetical philosophical conversation based on an impossible premise or thought experiment, that a living human brain could somehow have its billions of neurons and trillions of synaptic juctions, along with all the numberless interactions of chemo-electric potentials and other micro-processes associated with them, progressively replaced by microscopic mechano-electronic nanobots, while all the time remaining alive and functional.
Both protagonists reject dualism and the transmission (or rather transceiver) theory of mind, so the outcome was inevitable. Of course the subject would experience an imperceptible transition to machine consciousness, by the same token that there is an imperceptible transition of consciousness during life due to the successive replacement of living cells. Sure.
Far more likely (but still infinitesimally so) is the progressive destructive scanning of the brain down to the molecular level, with the microstructure revealed being converted into a vast digital data file.Then the (even more insurmountable) task of implementing a brain functional simulation processing that data file. This would also require simulation of the whole body/brain interface and the body interface with the outer world, or somehow interfacing with the original body kept alive throughout the process. Preposterous, but even if this were somehow possible it would be a poor decision for the subject, since it would inevitably result in death for the original person. Why would he care if a duplicate "clone" or multiple "clones" somehow resulted? He is still annihilated. In any case I think the magnitude of these tasks is so far beyond any forseeable techno capabilities that we can write such ideas off as pure fantasy.
Also both protagonists assume that physicalism is true and that personal identity is an illusion:
1. Personal identity is be same person from one moment to another.
2. There is nothing physical in a human being to remain the same from one moment to another (the cells are renewed, etc.).
3. All there is physical (physicalism).
4. Then we are not the same person from one moment to another because there is nothing in a human being to remain the same from one moment to another (personal identity is illusory).
I reject this argument rejecting the third premise: in addition to the physical may also exist structures. The child and the adult are the same person because a structure has emerged from another though physically they are not the same individual.
True, here is a physical / structure dualism, but conceiving the self as a structure not only we close to transhumanism, but that would allow us to understand the cases of apparitions and mediumship recorded by psychic researchers, although unfortunately these issues seem out of orbit these discussions ...