I thought I would post a few of Thomson’s most compelling arguments from her article “A Defense of Abortion” here (we are covering this in Social Ethics) for possible discussion:
Thomson takes a moderate view on abortion, arguing that is permissible in some cases but impermissible in others. She begins by, surprisingly, granting the pro-life view that personhood begins at conception. Most pro-lifers think that once you grant that point, the matter is settled. But Thomson tries to show that it is not, that the right to life just means you have the right to not be unjustly killed.
She relies heavily on analogies, and I will present two here:
Analogy 1: Imagine you are asleep, and while you are asleep you are hooked up to a famous violinist who can only be kept alive (for whatever reason) if he is hooked up to you. Obviously you did not consent to the violinist using your body, but disconnecting yourself from him would lead to his death. Thomson points out that, in this case, while it would be really really nice of you to remain hooked up to the violinist, no one would demand that you remain hooked up. In other words, it would be morally permissible to disconnect yourself from him.
Thomson is banking that most of us would agree on this, and uses this example to show that abortion – even if the unborn has a right to life – would be morally permissible in cases where the person did not consent to the unborn using their body to live (say, rape).
Analogy 2: IF it is the case that the morality of abortion hinges on whether or not the woman has consented to the unborn using her body (example 1 is supposed to show this), then what about this? – Imagine you own a home and install a top of the line alarm system to protect yourself from burglars. No alarm system is 100%, but say yours 99.8% effective. You dutifully arm the system every time you leave the home, lock the doors, etc. Of course, a burglar might still enter your home. But no one, Thomson suggests, would think that you have consented to the burglar being in your home just because you left your house unattended. After all, what more precautions could you have reasonably taken?
What does this have to do with abortion? Thomson argues that this analogy shows that abortion is also morally permissible in cases of failed contraception. The pill is (or can be if taken properly) 99.8% effective. By almost any measure that is a “reasonable precaution” and provides evidence of a refusal of consent for the “burglar” (sperm) to invade your “home” (egg).