The term “mental health” is everywhere, from government agendas, to educational reforms, to daily discourse. This is for good reason—hundreds of millions of people suffer from significant mental health concerns with a diagnosable mental disorder, let alone the fact that nearly all individuals have struggled with their mental health. The importance of mental health is uncontroversial, but the same cannot be said about its nature. Every practice related to mental health—which involves some of the most vulnerable people in the world—is committed to a conceptualization of mental health regardless of whether that practice is cognizant of this fact. Therefore, it is imperative to develop better answers to the questions of “what is mental health and why?” because conceptualizations of mental health systematically guide research, intervention, policy, and even how individuals strive to live their lives. I argue that the answer to the question of “what is mental health?” is that mental health is a causal nexus of positive facts. That is, mental health is to be identified with a cluster of positive facts that regularly co-occur such as resilience, hedonistic mental states like joy, high cognitive functioning like concentration, and productivity. The answer to the question “why is mental health what it is?” is that the positive facts regularly appear together due to the causal relations between them, rather than arbitrarily. For instance, resilience causes high cognitive functioning, which in turn causes resilience, which causes productivity, which causes high cognitive functioning and joy, and so forth. This explains why mental health is what it is because the causal relations between positive facts “glue” them together, causing them to regularly co-occur, thereby making them a stable category of existence that factors into epistemic practices such as induction and prediction. However, given the state of our knowledge, further empirical evidence is needed to elucidate the exact positive facts that constitute the mental health causal nexus and thus answer what mental health is. I provide a novel methodology—the anchoring analysis—that involves studying the mechanisms of causal interactions between potential positive facts to determine which are the most causally important and thus should be considered constitutive facts of mental health. Elucidating the homeostatic mechanism of the kind mental health is a daunting task; however, we only complicate matters for ourselves if we simplify the complexity of mental health. / Thesis / Candidate in Philosophy