The World Health Organization defines health as physical, mental, and social well-being, yet Western public health still tends to treat the social as a population-level variable captured by measurable indicators. Drawing on Husserl’s critique of naturalistic reductionism, this paper argues that such framing reifies persons and eclipses the lifeworld conditions through which health becomes intelligible in the first place. Extending Gadamer’s account of health as an invisible equilibrium, we propose that social health names a largely tacit background of trust, relevance, and belonging that is typically noticed only when it breaks down. Steinbock’s homeworld/alienworld dynamic shows why social equilibrium cannot be secured by exclusion. To articulate the vital dynamics of this equilibrium, we place Aristotle’s notion of entelechy in dialogue with Hedwig Conrad-Martius’s stratified anthropology (leiblich, affektiv-seelisch, geistig-seelisch) and Husserl’s account of empathy as the condition for intersubjective givenness. We define social health as the entelechial, affectively mediated capacity of persons and institutions to sustain and renew a shared homeworld that can integrate alienworlds, resonating with Buen Vivir’s relational and ecological conception of flourishing.