You wake up in the morning and find yourself back to back in bed with an unconscious violinist. A famous unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist's circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you, "Look, we're sorry the Society of Music Lovers did this to you—we would never have permitted it if we had known. But still, they did it, and the violinist now is plugged into you. To unplug you would be to kill him. But never mind, it's only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you.
Greater minds than mine have plucked this argument apart. Unstringing the Violinist is an excellent example. But what I want to do is what I did with the forced kidney donation argument: tweak it until it becomes more analogous to pregnancy.
First, to point out the areas where the Unconscious Violinist differs from pregnancy and abortion:
1. The unborn child is not a stranger.
2. Except in rare cases of rape pregnancy, the pregnant woman has engaged willingly in an act that she knew might leave her "hooked up" to her child.
3. Pregnancy does not, except in rare cases, leave a woman confined to bed. She is quite free to go about her business, albeit somewhat awkwardly in the later months.
4. Abortion is not merely "unplugging" the unborn child. It is taking active, usually violent, steps to kill him. He is poisoned or dismembered or stabbed.
So how do we re-draw Jarvis Thompson's picture, incorporating these differences?
First of all, we need to remove the existing emotional relationship between mother and child. The person in the thought experiment will be the father, who has only just found out that he had fathered the child in question.
We would have to put the man in a situation in which he knew he was placing a child at risk of being entirely dependent upon his body for survival. So let's posit that the man was engaging in a hobby that involves the use of chemicals that are fairly safe for adults, but are strongly toxic to a growing child's immature organs. Although he knows that having the chemicals around the house might cause a child to have kidney failure, he chose to have them there, and his child suffers kidney failure as a result.
Somehow we need to make the physical dependency one that does not utterly incapacitate the man. So let's make the child very young and portable, say, a newborn infant. The man does not have to remain in bed for nine months. Rather, he needs to remain connected to the child, but the child can be carried in a snugli. To make it even more like pregnancy, we'll say that the child is sedated the entire time so that crying and such would not interfere with work or social life. The child would just be bulky and awkward to carry around everywhere. The sickness and sedation would temporarily halt the child's growth and development. Once her kidneys have healed, and the sedation is reversed, her growth and development will take up where they had left off, but during the time that the man must carry her around, she will remain the size of a newborn.
Then we need to add the final difference. The man in our thought experiment isn't insisting that he had a right to unplug the infant and leave her to die. He is insisting that he has a right to demand that the doctor kill the child -- either by poisoning her or by dismemberment.
And let's remember -- the father knew from Day One that his hobby involving those chemicals might leave him in that situation, with a baby hooked up to him and utterly dependent upon him for nine months. He indulged in his hobby anyway.
Does it look different now?