This chapter provides background about the concept of bioethics and the history of the discipline, explaining the motivations for the book and outlining the subsequent chapters. A satisfactory work in bioethical theory, as we intend to provide, would accomplish three aims: (1) provide a high-quality discussion of ethical theory and methodology in ethics, (2) avoid the narrowness of normative vision that one finds in some theories (e.g., on hypothetical agreement in contract theory, on liberty in libertarianism, on moral rules in a rule-based approach), and (3) integrate areas of philosophical theory that are often neglected in theories of bioethics such as the nature of harm, the nature of well-being, models of moral status, personal identity theory, and the “nonidentity problem.”

This chapter outlines our dual value theory. At the most general level, the theory consists of two substantive values, a formal distributive principle, and a scope determining the set of beings with moral status. The two values are well-being and respect for rights-holders. The distributive principle is equal consideration for all beings with moral status. And the scope is the set of sentient beings. Although our approach confers equal moral consideration on all sentient beings, it does not regard all sentient beings as rights-holders. On the basis of these ideas, we specify mid-level principles pertaining to nonmaleficence, beneficence, distributive justice, and autonomy rights. We also explain the key respects in which our theory differs from the principle-based approach of Tom Beauchamp and James Childress, and comment on other types of ethical theory.