The Ethics of Killing: Strengthening the Substance View with Time-relative Interests.

The substance view is an account of personhood that regards all human beings as possessing instrinsic value and moral status equivalent to that of an adult human being. Consequently, substance view proponents typically regard abortion as impermissible in most circumstances. The substance view, however, has difficulty accounting for certain intuitions regarding the badness of death for embryos and fetuses, and the wrongness of killing them. Jeff McMahan's time-relative interest account is designed to cater for such intuitions, and so I present a proposal for strengthening the substance view by incorporating McMahan's account - the Dual-Aspect Account of the morality of killing. I show that it resolves some important issues for the substance view while preserving its central premise of moral equality for all human beings. I then compare the Dual-Aspect Account with McMahan's Two-Tiered Account of the morality of killing, which he derives from his time-relative interest account.