What is the Common Morality, Really?

In recent editions of Tom Beauchamp and James Childress' Principles of Biomedical Ethics, their famous principles have been deployed as elements of the common morality recruited to anchor bioethical reasoning. In Principles, however, Beauchamp and Childress defend neither their assertions about the content, nor the normativity, of the common morality. Because these content and normativity claims form the backbone of their approach, both claims deserve substantive support if the project of Principles is to be completed. Defense of the normativity claim remains an issue that has to date gone underdeveloped in the literature. Here I evaluate three ways of mounting such a defense, arguing that only one-conceptual analysis demonstrating the principles to be part of the "definitional criteria" of morality-might succeed within the confines of Beauchamp and Childress' metaethical paradigm. I argue further that identification of the common morality with these "definitional criteria" presents a compelling way forward.