The notorious World Health Organization definition of health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” has been roundly criticized by philosophers more or less since it first appeared in 1948. Despite its conceptual, and practical, limitations, it launched a highly productive debate about the nature of health in which two major strategies have dominated: a descriptive or naturalistic approach in which health is operationally defined in terms of normal functioning understood entirely in the language of the biological sciences and a normative approach which insists that health cannot be understood until the salient fact that health is a human good is explained. This debate has revealed a dilemma: any philosophically acceptable definition of health must make a place for our powerful intuitions that health is both intrinsically and instrumentally valuable. Yet, unless the notion is firmly grounded in the biological sciences, susceptible to operationalization and measurable, it threatens to lose its scientific legitimacy. WHO has more recently and with far less fanfare developed another definition of health “for measurement purposes” that recognizes the force of the dilemma and attempts, with debatable success, to address it.