The Invention of Morel is, at its core, a treatise upon the nature of man's quest for immortality. Morel, a modern-day Gilgamesh, seeks to rectify what he sees as the ultimate flaw of man: his transience. By preserving himself and his friends by means of recording and continual re-projection, he believes that their souls will be transferred to the indelible and unalterable copies, thus effectively rendering them immortal. His reasoning for doing so relies on the underlying assumption that only the mind and the soul are worth preserving; saving the human body from decay is impossible and inefficient.
In a novel approach to the issue, the author makes the protagonist of the story completely removed from the issue. He is simply a coincidental observer of Morel's efforts; the quest for immortality has been completed in a previous life, and the narrator is merely watching its effects. This imaginative approach allows a view of the topic that is natural and necessary (a view of eternity a little farther down the road) that is impossible when the story drops the reader in medias res. The artistic flair of perceiving Morel's quest through the psychotic and hallucinatory perspective of a paranoid fugitive lends the novel a sophisticated air, bringing the factor of questionable perception into the grey equation of the effects of an attempt at immortality.
It is important to analyze Morel's success in his endeavor. Did he really succeed? True, his copies will, barring some disaster or destruction of the machine, continue to project themselves forever. They are indestructible and incorruptible; they will continue to live the same pleasant week over and over into eternity. Much of Morel's success depends on the validity of his assumption that the soul is transferred into the new bodies, as he theorizes based on the evidence of the decay of the original bodies following capture. This evidence, as noted by one of Morel's friends/victims, is questionable at best. This aspect gives Morel an entirely new look: instead of a benevolent bestower of immortality, he's a thief and a murderer.
Even if his experiment succeeded, and the subjects' souls did transfer into their copies, the question still remains: is that kind of "life" (the ceaseless, unalterable repetition of a period of life) even really life at all? Biologically, perhaps. But the view of Casares here seems to be on the negative side: by making his paranoid, obviously delusional narrator join the eternity experiment with his dying energy as he physically falls apart from the effects of the machine, he paints an unpleasant picture of sacrificing one's present for the sake of the unnatural and even inhuman future.