This is an issue on which I expect disagreement, and it's not unreasonable to think fetuses have some kind of right to life at the beginning of the third trimester when pain perception begins. (Personally, I think that fetal anesthesia should be required at that point for abortions, though the fact that the fetus is still probably below many animals' mental capacities makes it incorrect to attribute a right to life beyond that of animals.) A big part of the reason that many people think the right to life begins earlier, I'd say, is because they're simply confused about the nature of the fetus' mind, and fall into the ancient human temptation to posit minds where there aren't any. |The Ethical Werewolf|
Neil seems to think that pain perception is not morally significant enough to affect the permissibility of abortion, but is morally significant enough to warrant concern for the suffering of the pain perceiving entity. That's kind of an odd view on its face, but maybe Neil's idea is just that fetal pain matters but not as much as a woman's bodily sovereignty.
Fair enough, but he also pretty clearly holds that the third trimester fetus lacks a mind. What I don't understand is, how can unminded pain possibly matter in moral calculations? In a stripped down sense, purely biological pain is a mere signal. In a being without thoughts, plans, or understanding that signal can't map onto anything like our concept of pain. The signal can't, that is, have any content. What, then, is it about the pain that's supposed to be morally relevant?
1 'Having a mind' meaning, in this case, being the sort of being which is disposed to do things like make plans, hold intentions, and ask questions. Which I mention to highlight the fact that having a mind is not the same thing as having a brain.