This isn't exactly a teaching question, although it seems that just about any philosophy question can be turned into one by adding, "And how would you teach this?" My question is what the best arguments for thinking that (early) fetuses are persons, or what's the best way to present this point of view. I think I may be too close to some of these issues, in terms of some research interests, to step back and see things from a more helpful perspective for classes.
Here's a bit of background. To avoid it, skip to *** below.
My general strategy for teaching the abortion issue is to first distinguish a number of conclusions that one could hold on the topic, e.g., that it's always wrong, always permissible, sometimes wrong (in what circumstances?), sometimes permissible (in what circumstances?) and even perhaps sometimes obligatory (in what circumstances?). My goal here is to encourage them to become more precise in their conclusions, avoid slogan-mongering and make it clear that more complex views on abortion are possible, such that some are (or could be) wrong because of some reasons, whereas others could be permissible because of some reasons, etc. (I use this nice page from Fred Feldman to help with this).
Once more precise conclusions are distinguished, I tell them we are going to overlook some of this precision for a bit (!!) and have them break up into groups to develop lists of as many reasons as they have ever heard anyone give in favor of thinking that most abortions are wrong or abortions tend to be wrong, as well as a view that most abortions are permissible or they typically are. I then focus on the arguments for views that abortion is wrong.
Students tend to initially give lots of responses that are "question-begging" or close to it: it's wrong because it's murder, because it's a bad choice, because there are better options (like adoption), and because it's irresponsible and because it's wrong to end pregnancies. They have some better arguments as well, but I tend to have to provide them with the kinds of arguments that philosophers tend to focus on.
Eventually we get to personhood arguments. I am not at all impressed when folks just say "Here's what persons really are" and then give some Locke-inspired definition (I believe Mary Anne Warren just "suggests" her view on personhood), since someone can easily respond, "Well, I just don't accept your definition." So what I do is some kind of "inference to the best explanation" type exercise where we identify some clear cases of non-persons, some clear(er) cases of persons (including fictional and otherwise possible but perhaps not actual persons) and then try to figure out - from these clearer cases - what makes persons persons and why non-persons are non-persons. We then arrive at something like Warren's view, but with some reasoning behind it, instead of a mere suggestion.
The problem, if it is a problem, is that on this view early fetuses are clearly not persons. However, obviously some people do claim that fetuses are persons and so I am wondering what, if anything, can be said in favor of this (or, at least, what anyone says to one's students in favor of this!). One thing I try to point out is although many people think that -- if fetuses are not persons, then abortion is permissible -- this is not true because abortion could be wrong even if fetuses are not persons; they could be non-persons for whom there could be excellent moral reasons to not kill. I think my fixation on this fact has given me some mental block to seeing why people might think that early fetuses are persons.
Folks will say, "Yes, these fetuses are not concious, sentient, rational, communicative, etc. beings, yet they are persons nevertheless," so clearly they reject the Lockean view (or at least deny that meeting its criteria is necessary for personhood). I don't like to think that these people are saying something that is analytically false; I think they just have a different view on what persons are.
They then might propose that all living human organisms are persons, that if something is a living human organism then it is a person. This is a view, although what would be of interest would be the reasons that could be given in favor of it.
My speculation is that, for many people, "a person" just means something like "a being with high moral value," "a being that is wrong to kill," or whatnot, some purely moral definition, perhaps with no psychological component built into it. Is this what many people (including students) often mean by person? Is this definition false?!
Sorry for this long post. Perhaps someone out there has had similar bewilderment about personhood, how the term is often used, how you might figure out what persons "really" are, and so on and can help me out. Thanks!