In Don Marquis’ paper “An Argument that Abortion is Wrong”, he argues abortion is morally wrong for the same reason as murder. His argument is different from the standard pro-life argument that stress that the fetus is both human and alive, therefore the fetus has right to life. By using a different approach, Don Marquis’ argument avoids the controversial in the debate of whether fetus is qualified as a human whom process the right to life.
Marquis starts his argument with asking why killing an adult human is wrong. (p.130) Killing is wrong because killing deprives the victim of a future value. The killing victim suffers the misfortune of a premature death which consists of the loss to the victim of the future goods of the consciousness. In general, killing is wrong because it deprives the victim of a future like ours (FLO).
Marquis then further explains the FLO theory is a sufficient reason for killing is wrong. First he argues the nature of misfortune in terminal disease is the loss of FLO, which also the same for premature death. He also argues murder is the worst crime because it deprives the victim all of his future, not merely part of it. Then he argues the FLO theory does not the pit-falls of traditional pro-life arguments. The FLO theory is compatible with euthanasia because those who seek euthanasia have no future. The FLO theory has no implication to animal rights, since animal life is not a life like ours. Therefore why killing is wrong can be explained using the FLO theory alone. At last he applies the FLO theory to abortion. Killing fetuses deprive the FLO of the fetuses, therefore abortion is immoral. (p.133)
The FLO theory seems to provide a sound argument on why abortion is immoral. However under strict scrutiny, the FLO theory actually contradicts to Marquis’ own view on abortion (p.84) . In the beginning of his essay, Marquis stated abortion is not immoral under rare instances. “Such cases include abortion after rape and abortion during the first fourteen days after conception when there is an argument that the fetus is not definitely an individual.” (p.126). If the morality of abortion is judged by the FLO theory alone, there should be no exceptional cases for fetuses from rapes and fetuses under fourteen days old. The fetuses from rapes have the same FLO as other fetuses, so their abortion should also be immoral. In the case of the first two weeks post conception, twinning is possible; abortion may cause the loss of FLO for two individuals instead of one. Killing those fetuses deprives their FLO(s); therefore abortion is also wrong in these cases.
Marquis did not explain the criteria to make abortion moral for the rare cases in his paper. It is obvious that using FLO theory cannot grant him the morality of abortion in the rare cases he stated.s In order to defense his view, he may attempt to use traditional moral theories, such as Unitarianism, Categorical Imperatives or Social Contract Theory, to overrule the FLO theory in the rare cases. Regardless of which moral theory he chooses to defense the exceptions, once he introduces a moral theory other than the FLO theory into his argument, he opens the flood gate allow us to re-evaluate the morality for the not so rare cases. Is kill fetuses from rape ok because the mother does not want the baby? Why not extend the fourteen days limit to the 3rd trimester? If there are fundamental moral principles that can overrule the FLO theory, according to the Occam’s razor, why can’t we simply use the fundamental moral principle and get rid of the FLO theory?
Until Marquis come up with satisfying explanation for morality of abortion in the rare cases or he can explain away the future good of those fetuses. He must either withhold the application of FLO theory to abortion for not contradicting himself or he must revise his view to accept abortion is wrong even in those rare cases.
 P.84 In addition, Marquis mentions as exceptions cases of rapes, when the fetus is anencephalic (partially or completely lacking a brain), and when the abortion is performed during the first fourteen days after conception. Given the number of these exceptions he allows himself at the outset, it tempting to say that Marquis is really a moderate rather than strictly pro-life, but because his emphasis is on the claim that abortion is seriously wrong, I will put him in the pro-life camp.