I do disagree with Mr. Lem though that "clone immortality" is impossible (though it requires me to "bite the bullet" and accept some bizarre conclusions). One of the arguments that Lem presented for clone immortality is as follows...
For me to claim that clone immortality is possible, then I should believe that two clones of a person, if they both exist at the same time, are both the same person. I'm willing to accept that, so long as both clones' memories are "in sync" with one another, so they both experience and believe in exactly the same things at exactly the same time. It is a bizarre conclusion though, and it is one that Hylas rejected out-of-hand as being absurd.HYLAS: ... Well, I am drawing an equilateral triangle. If I draw a second one, I can say that both have "the same" structural property of being equilateral. I can draw many such triangles, but from a structural point of view they are actually just one single triangle, repeated many times. In the same way I can say that all Hylasses which have been created by the machine are actually "the same" human, being simply repeated x times. What do you think about that?
PHILONOUS: You gave a very clear presentation of the matter. Do you permit me to create a copy right now already, while you are still alive?
HYLAS: Why that?
PHILONOUS: Well, since the copy is no different person, but simply "the same", and since, as you said yourself, from a subjective point of view (and this is the one that it's all about) it is "the same" human being as yourself, it follows that you - when the tyrant has killed you, but the copy stays alive - will be alive, since a person will continue to exist which is "the same" Hylas as you. Or do you take a different view?
As a side-note, Mr. Lem also wrote Memoirs Found In A Bathtub, a book that (I believe) was recommended in Paranoia XP as a source material for the STRAIGHT playing style.