Think about a slave-holding. Why not hold slaves?
One reason may be that we think there are these entities, call them "persons." And these persons have certain minimal rights - let's just take two commonly mentioned examples: the right to life and liberty.
Now if we think that there are persons and that persons do have the minimal rights to life and liberty, then we can straightforwardly answer the question "why not hold slaves?" And the answer would then be: One should not hold slaves because slavery plausibly violates the minimal rights of persons (in this case, slaves).
But let's consider a recalcitrant slave-holder. That is, let's consider the slave-holder, call him "Caligula," who maintains that his slaves simply are not persons. They are, he says, his property. Therefore, says Caligula, since his slaves are non-persons, he violates no rights in holding them as slaves and he can do what he likes with them.
What I am interested in is what we might say to Caligula.
For sure, several avenues seem open to us. For example, if we have genetic theory at our disposal, we might appeal to a chromosome analysis. One option might be that we simply count the chromosomes looking for a particular number which number (we have decided in advance) marks out "persons" in the relevant sense - say, just to pick a random number: 46. We then might say that any entity that has the requisite number counts as a person. This lead to to troublesome cases - for example, where genetic disorders are present in entities that we might otherwise want to consider persons. But we could perhaps go the genetic route. Before we do so, though, let us explore another option.
We might instead appeal to some axiom - whether religious or philosophical. And here (as the reader might now expect), we could immediately go a "religious" direction. But I want to resist such a direction (at least for the moment) and try an alternative approach (say as a sort of thought experiment).
And it seems to me that there is an obvious alternative candidate. Let me call this candidate "the liberal axiom." And here I mean to trade on a sense of "liberal" whereby the word designates generosity.
So here's the axiom:
The Liberal Axiom: If there is a genuine question as to whether something is a person, let's be generous and say that it is a person.
I think that this axiom has several things going for it. Firstly, I think that it yields the results that we want in slave cases. That is, it turns out that slaves will be counted as persons, simply because there is a genuine question about person-hood in the slave cases. That is, Caligula asserts that his slaves are not persons. But as many rational people have raised doubts about his assertions, there is a genuine question as to whether his slaves are persons. Of course Caligula will assert that he can do what he wants with his own property. But although we might agree that if something really is Caligula's property, then he really could do what he wanted with it. This consideration only applies to a slave if a slave is the sort of thing can that be property. And if a slave really is a person, then we will say that since a person is not the sort of thing that can (justly) be property, Caligula cannot do want he wants with "slaves" because he doesn't (justly) have any claim over them. His assertions to the contrary hardly count as any sort of demonstration - let alone a satisfying demonstration. We could say that, in effect, we put the burden on Caligula to demonstrate that his slaves are not persons. Unless or until he does this, we're justified (besides being generous) in assuming that they are persons.
Additionally, "The Liberal Axiom" makes it "easy" for us to respond to Caligula.By "easy" I mean that we don't have to get bogged down in genetic testing or any technical discussion. I think that genetics route is not altogether hopeless. On the contrary, I think that it has great potential. But, it is, despite it's potential, very sterile, mechanical, and reactive (like we're trying to label a test tube correctly). On the other hand, our axiom seems very organic, social, and proactive (like we're trying to make friends, in other words).
Furthermore, I think that (what I am calling) "The Liberal Axiom" comports fairly closely with other closely associated postures of generosity that we normally associate with "progressive" or "politically liberal"-leaning people. For example, consider the question of whether to give money to a particular person who appears to be homeless. As a first pass, one might think that a (species of) non-liberal position would be to say something like that, "Well, the person who appears to be homeless might be shamming. Or, even if the person is genuinely homeless, he might use our money to buy booze instead of food", or something. And it seems to me that a more liberal approach (in my sense and in something more like the "usual" sense) would be to say, "You know, it's better that we do give the money and it turn out that the person did not need it than that we do not give the money and it turn out that the person did need it. So, let's be generous, and give it."
So, now, let's think about abortion. Why not abort?
One reason may be that we think there are these entities, call them
"persons." And these persons have certain minimal rights - let's just
take two commonly mentioned examples: the right to life and liberty.
This should sound familiar. Earlier we considered the very same things with respect to slaves. In this case, if we think that there are persons and that persons do have the
minimal rights to life and liberty, then we can straightforwardly answer
the question "why not abort?" by giving a similar answer: One
should not abort because abortion violates the minimal
rights of persons (in this case, unborn babies - "fetuses").
But let's consider a recalcitrant mother (pregnant woman). That is, let's consider a mother, call her "Herodias," who maintains that her unborn baby ("fetus") simply is not a person. She may say, similar to what Caligula said about his slaves, that the thing in her womb is her property. Therefore, says Herodias, since her baby is a non-person (her property), she violates no rights in aborting.
As before, let's forego (for the present) traveling down the paths of genetics or religion (as promising as those roads may well be). And let us instead appeal right away to "The Liberal Axiom."
There is a question as to whether the entity in her womb is a person. So, let's be generous and say that it is a person. Or, to put it another way: Let's be liberal about our assumptions of person-hood.
But if we do so, then we must say, just as we said to Caligula: If the entity in question is a person, then it is not the sort of thing that can be another person's property. Rather, it's the sort of thing that should enjoy the basic rights of life and liberty.
And this it seems to me is one of the core values that people who call themselves "liberals" usually prize: Standing up for the basic rights of persons (whoever they may be) - especially those who are voiceless. But, what I think is prior to this, is that we stand up more fundamentally for the recognition of the voiceless (whoever they may be) as persons in the first place. And that's why it seems to me that it is really opposition to abortion that is the truly liberal thing to do.