Seneca expresses the Stoic understanding that individual wellbeing is intimately connected to collective wellbeing. We cannot be truly healthy, happy, or successful if the communities and systems we're part of are dysfunctional or unjust. This insight calls us beyond narrow self-interest to consider how our actions affect the larger whole - our families, communities, society, and even humanity as a whole. True self-interest is enlightened self-interest that recognizes our fundamental interdependence. Working for the common good isn't just altruistic but practical wisdom that creates conditions for our own flourishing.