Final answer:
Marquis relies on the claim that abortion is morally wrong because it involves the killing of a being with a valuable future. He argues that fetuses have the same potential for a valuable future as adult human beings.
Step-by-step explanation:
In his argument against abortion, Marquis relies on the claim that abortion is morally wrong because it involves the killing of a being with a valuable future. He argues that what makes killing wrong is not the loss of conscious experiences, but the deprivation of a valuable future.
Marquis suggests that fetuses have the same potential for a valuable future as adult human beings, and therefore, killing them through abortion is morally equivalent to killing an adult human.
By focusing on the potentiality of a future like ours, Marquis challenges the commonly held belief that the wrongness of killing lies in the loss of current experiences or desires.