The two most important questions for ethical public health.

Public health ethics is a distinct and established field, and it is important that its approaches and rationales are understood widely in the public health community. Such understanding includes the capacity to identify and combine principled and practical concerns in public health. In this paper, we present a background to the ideas that motivate public health ethics as a field of research and practice, and rationalize these through a critical ethico-legal approach to analysis. Two essential points of inquiry are identified and formulated to allow philosophical and practical agendas regarding public health to be combined. These come through asking the theoretical question 'what makes health public?'; and the practical question 'how do we make health public?'. We argue that these two questions require to be addressed if we are to achieve a robust and rigorous, ethical public health.