In a recent response by Eddy Nahmias, he ended up talking about "the capacities [which] are the grounds for personhood". That made me think about arguments on abortion. Some pro-life people argue that the important thing is not the capacities some being HAS, but those that it can COME TO HAVE in some specified way (e.g., a "natural" way, or a way that is grounded on that being's "essence"). And that, they say, is what makes every fetus a person, and what makes a temporarily unconscious human a person. Both have to undergo some CHANGE before they can display specifically human traits that are important for personhood. Now, I don't find this argument very persuasive, but I really do not have a good answer to it. Could you tell me what is the difference (if any) between a one week human fetus and an unconscious adult that makes the latter a person, but not the former?