If the wrongness of killing were based only on being aware of the world, it would be difficult to explain why killing a human being is more morally serious than killing a squirrel, since both have some level of awareness. Raising the standard to self-awareness doesn’t solve the problem either. Human infants are not self-aware, yet nearly everyone agrees that killing an infant is gravely wrong. That gap between theory and moral intuition shows that neither awareness nor self-awareness can adequately explain why human life has special moral value.
These difficulties point toward a deeper foundation for the wrongness of killing—one that does not fluctuate with mental abilities or developmental stage. Grounding equal rights in human nature itself provides that foundation. Human nature applies equally to all humans: infants, adults, the disabled, and those temporarily lacking certain capacities. When moral worth depends on what kind of being someone is, rather than what they can currently do, human equality is preserved without arbitrary exclusions. From this perspective, protecting unborn humans follows naturally from the same reasoning that protects infants and other vulnerable members of the human family.
Key Takeaways
If awareness or self-awareness determined moral worth, infants would lack protection, which contradicts widely held moral judgments.
Basing rights on mental abilities creates arbitrary hierarchies where some humans count less than others.
Grounding rights in shared human nature preserves true equality across all stages of life.
If unborn humans share the same human nature as infants and adults, consistency requires opposing their intentional killing.