I’m not making the argument that you think I’m making.
Bodily autonomy as a fundamental right
Bodily autonomy is a fundamental moral principle because it makes sense of my moral intuitions. I intuit that it’s wrong to rape. It can’t be because of the physical harm, because it’s still intuitively wrong to rape someone if you drug them and are gentle. It can’t be because of the mental harm, because it’s still intuitively wrong to rape them if they’re unconscious and will never know. Murder is wrong and remains wrong even if it causes no pain, even if the murdered person is unaware that they are being murdered. In both of these cases, you’re using someone else’s body without their consent.
This principle, that people should be able to control who can use or modify their body, and for what, is an assumption in the same way that you’ve described other fundamental moral principles- because it makes sense of our intuitions. Once we derive the principle from our intuitions, we can use it to clarify edge cases. To take one example- assisted suicide. Is it wrong? Bodily autonomy says no. If someone asks you to kill them and they sincerely want to die, then it’s not wrong. This is borne out when we compare what the principle says to what we see in society: while there are any number of (valid) concerns involving coercion, informed consent, and mental health, there are also hundreds of stories and legends about human beings helping each other to die. That it happens is tragic, but the act itself is intuitively morally permissible.
To me, the idea that bodily autonomy is a fundamental moral principle seems fairly obvious, and I think it’s obvious to most people when not discussing abortion. If someone is using your body without your consent, you feel morally justified in rejecting them.
My view on abortion
As I said at the start, I’m not making the argument that you think that I’m making. I don’t intuitively consider a fertilized egg to be a person, but I do intuitively consider a five-year-old to be a person. I’m not sure where you would draw a line to divide non-person from person and so I don’t: I assume that everything from conception onward counts as a person because it seems good to err on the side of granting person-hood when in doubt.
I still support abortion until viability.
We have two people, one of whom is using the other in order to survive. My fundamental moral principle of bodily autonomy says that the person being used can withdraw their consent and reject the use of their body. But, in this case, the user will die if they are rejected. Does the principle still hold? Does one person’s right to life trump another person’s bodily autonomy? If I concoct alternative scenarios in which the same rights are at odds, my intuitions seem to come down on the side of bodily autonomy.
Some scenarios
The scenarios
Imagine that two people are drowning in the ocean and one can’t swim. The non-swimmer clings to the swimmer, who is able to support them both but with an increased risk of drowning. The swimmer finally shrugs off the non-swimmer and the non-swimmer drowns.
I intuitively feel that a virtuous person would have struggled on and done their best to save the non-swimmer. That would be the heroic thing to do. Refusing to support the non-swimmer, however, is morally permissible. This scenario isn’t as good an analogy as it could be, because there’s no direct bodily violation, but two agents relying on each other to act in particular ways. Lets see if we can find something more directly applicable.
Imagine that one person agrees to have their body surgically connected to another in such a way that their organs will do the work of keeping both people alive. The supporting person finally requests that they be separated again, killing the supported person.
Much as in the previous scenario, I can feel both that the virtuous thing to do would be to soldier on and that it’s morally permissible to make the decision to leave the supported person to die- in fact, I feel that it’s more morally permissible than in the last scenario. Crucially, in this scenario, one is actually violating the body of the other, rather than relying on them to act in a particular way. What happens if we go the other way?
Imagine that one person is sitting by a pond when they suddenly realize that another person is drowning. They decide that, for whatever reason, they will not act to save the person’s life.
I feel that a virtuous person would act to save the drowning person, obviously. My moral intuitions about what should and shouldn’t be permissible are torn, in this case. In general, they still grudgingly come down on the side of the person failing to act, but there are caveats and special cases. Looking at the law as a proxy for what society feels on the subject, I see that they mostly agree with me.
My conclusion
In each of these scenarios, one person is refusing to allow their body to be used by another when the life of the other is on the line. In each scenario, my intuitions come down on the side of the person doing the refusing- strongly, when the use is direct and invasive, weakly when it involves independent behavior and action. So bodily autonomy seems to hold as a fundamental principle.
Application To abortion
During a pregnancy, we have two people, one of whom is using the other in order to survive. The mother decides that she no longer wishes to allow the use of her body, and gets an abortion. Much as in the previous examples, I may consider it virtuous to carry the child to term, but I can’t deny that she should have the fundamental right to reject the non-consensual use of her body.
At this point, I think it should be clear why I think this.
Abortion, of course, is more than just denying someone the use of your body- it involves killing the fetus as well. If the fetus can’t survive on it’s own in the world, then arguing about this is, to me, moral hair-splitting. Person or not, killed by a doctor or killed by exposure, the fetus is still dead. Where I deviate from the standard liberal position on abortion is when the fetus can survive on it’s own. At that point (and granted, that “point” is more of a gray area), both the mother’s right to bodily autonomy and the fetus’ right to life can be upheld and it now matters whether the fetus counts as a person.
My rule of thumb, as I said earlier, is to err on the side of person-hood when in doubt and so I think that post-viability abortions are not morally permissible.