These are really tough and fascinating questions, both about what capacities are and what persons are. I hope other panelists might add to what little I have to say. What I will say (briefly, and without checking to see what the relevant literature has to say) is that one way to understand capacities is this: An object X has a capacity C to perform C-relevant functions or behaviors (C-stuff) if and only if X has a structural organization O such that, when X is in the appropriate circumstances, O allows X to do C-stuff. For example, I have the capacity to multiply any two numbers 1-13 because some structure in my brain allows me to get the right answer when the circumstances arise (e.g., when I'm asked to multiply 8 x 9 and I am awake and paying attention, etc.). Having a capacity to do C-stuff can be distinguished from having the potential to develop the capacity to do C-stuff. The potential might involve being in a position (both structurally and environmentally) to develop the...

That's a clever argument. It looks like the form is valid. The problem is with premise 3 (it's better to choose option where fetus is definitely not immorally killed ...). Whether that premise is true seems to depend on whether there may be other reasons why the abortion may be justified that outweigh the possibility that the fetus is immorally killed, and of course, it's hard to assess the premise without more information about the likelihood that killing the fetus is actually immoral. This structurally parallel argument should help illustrate the problem: 1. If a woman does not have an abortion, then maybe the fetus will grow up to do horribly immoral things. 2. If this woman does have an abortion, then the fetus will definitely not grow up to do horribly immoral things. 3. It is better to choose an option where the fetus is definitely not going to grow up to do horribly immoral things, rather than an option where the fetus may grow up to do horribly immoral things. 4....

Let's try some analogies. Suppose U.S. citizens have a constitutionally guaranteed right to vote for President, congressional representatives, etc. Now suppose that anyone who sets up or runs a voting booth is prosecuted for violating a law that says providing outlets for voting is illegal. It seems that this law would violate our constitutional rights. Or try it with the Second Amendment. In general, it is unconstitutional to bar selling guns as well as buying them, presumably since it would violate our right to bear arms if there were no way to get them. Accused defendents' right to legal counsel would be violated if it were illegal to practice law. And so on. I think that the way you set up the question, by supposing women have a right to abortion, suggests the answer: it would violate that right to make laws entirely restricting doctors from providing abortions. However, if you did not make that initial assumption about women's right to abortion, then it seems there is...