Some abortion-choice advocates do not see the status of the unborn as the decisive factor in whether abortion is morally justified. They argue that a pregnant woman's removal of the unborn from her body, even though it is foreseeable that it will result in the unborn's death, is no more immoral than an ordinary person's refusal to donate his kidney to another in need of one, even though this refusal will probably result in the death of the prospective recipient.

In 1971, philosopher Judith Jarvis Thomson published what would become the most famous and influential argument of this sort. Others, including David Boonin and Eileen McDonagh, have defended revised versions of it. The focus of this chapter will be on Thomson's argument as well as refinements of it found in these other works.

THOMSON'S ARGUMENT

Thomson writes that it is “of great interest to ask what happens if, for the sake of argument, we allow the premise [that the unborn is intrinsically valuable (IV)]. How, precisely, are we supposed to get from there to the conclusion that abortion is morally impermissible?” Thomson's argument, therefore, poses a special difficulty for the pro-life advocate. She grants, for the sake of argument, the pro-lifer's most important premise – the unborn is a subject of moral rights – but nevertheless concludes that abortion is morally permissible.