The first two chapters of this book address two fundamental (and related) questions in the Philosophy of Public Health: first, the nature of “health” when applied at the population level, and second, the goals of public health as a discipline/profession. Since public health (the discipline) can broadly be understood as having the “primary purpose of protecting and improving the health of the public” (Childress et al. 2002), before identifying the goals of public health, one must first understand what improving the health of the public amounts to. In this first chapter, I consider the view that “health” is a property at best applicable only metaphorically to populations, since a non-metaphorical reading would require reifying populations as if they were “a natural thing—an organic whole with its own interests, needs, and being” (Jennings 2007, p. 54) (See Giroux (2021) for further discussion). If populations are not “natural things”, they argue, health can only truly be considered a property of individual organisms and their physiological parts. I reject this view, arguing instead that health is a property of complex biological systems, and further that many animal populations, including some human populations, qualify as complex systems suitable for instantiating the health property.