I think you are getting confused with your "I"s by assuming that the "I" can't be duplicated.
In the hypothetical at the moment of creation of the copy there would be no way of distinguishing the two apart using their "consciousness". Where there was one "cos" there are now two individuals that both feel and think they are "cos". Both have the same memories of being conscious, both would be able to relate what happened to them when they had their first kiss and so on. So just like the number of eyes, legs, arms and so on have been duplicated so has the number of "I"s.
Everything has been duplicated. However once they start experiencing different stimulus the "I"s will start to diverge and therefore killing either the copy or the original would be killing a fully conscious being. If you killed the original the copy would still think of himself as "cos" and vice-a-versa since we only experience out own consciousness.
In the hypothetical at the moment of creation of the copy there would be no way of distinguishing the two apart using their "consciousness". Where there was one "cos" there are now two individuals that both feel and think they are "cos". Both have the same memories of being conscious, both would be able to relate what happened to them when they had their first kiss and so on. So just like the number of eyes, legs, arms and so on have been duplicated so has the number of "I"s.
Everything has been duplicated. However once they start experiencing different stimulus the "I"s will start to diverge and therefore killing either the copy or the original would be killing a fully conscious being. If you killed the original the copy would still think of himself as "cos" and vice-a-versa since we only experience out own consciousness.