This thesis examines metaphysics in order to re-present Māori and indigenous understandings of Being and deconstruct the notion of mental illness. A holistic understanding of Being is crucial to Māori and indigenous worldviews and takes priority as a focus for this thesis. Holistic notions of Being allow indigenous peoples to reimagine potentiality in general and the possibility of a renewed experience of being-in-the-world more specifically. Through an exploration of Māori and indigenous (complex) holism, I seek to re-turn to the influence of things in the world that exist outside of the self-contained individual - that is, beyond the cognitive rational agent. Doing so shifts the concept of well-being to reside not simply within the person (or the individual’s reactions), but within the entire world in which we live. It is posited that a dominant Western metaphysics poses a fundamental risk to Māori and indigenous expressions of Being. This deeper layer of influence – the metaphysics of presence - is examined to expose its structure – one that insists that things in the world will be represented as fully discernible objects. The implications that a dominant Western metaphysics has for the notion of mental illness are explored within the context of the metaphysics of presence that sets up things in the world as Beings whose essential meaning is identified only through qualities that can be seen, measured, described and defined. Within this view of the world, the notion of mental illness is solidified, reflected in a focus on the most discernible aspects of Being – the observable and physical parts of a person that can be examined through science. To counter this, the more mysterious and unthinkable aspects of Being reflected in Māori and indigenous metaphysics are highlighted as a way of re-turning to holism, to the extent that they resist the expectation that things in the world will be reduced to fit the dominant (metaphysical) framework. I engage the relational holistic research approach of whaiwhakaaro (a non-method implicating the more-than-human entities that push thinking and characterised by a free-flowing style of reflection), to draw out the possibilities that exist for re-presenting Māori and indigenous metaphysics and the notion of mental illness. Eleven interviews were conducted with participants from varying professional and community-based backgrounds. While the participants represent different views on metaphysics and mental illness, each has a passion for exploring the philosophies that shape the experience of being-in-the-world and how we understand ourselves in relation to all other things. Their responses provide important signals for how human nature, more-than-human nature, and (mental) well-being are re-conceptualised. The main ideas that emerged through the interviews and the process of reflecting on participant responses (whaiwhakaaro) provoked thinking about the possibilities of holism in reconsidering the notion of mental illness. Māori and indigenous understandings of Being were used to re-turn to ideas of well-being as a collective experience. I posit that, if there is illness, then it resides in the world rather than being centred solely on the individual who experiences the world. If there is a way to talk about illness and well-being, then it need not be restricted to assigned concepts or pre-determined categories that explain behaviour. Through a re-turn to complex holism – to Māori and indigenous metaphysical premises – I suggest we can engage with people’s experiences on different terms. These are the terms that carry excessive meaning, that allow for mystery – to break from conventions and categories. These terms support a different view of individualism where the person is free to express their experience of thorough interconnection – of whakapapa. In its broadest sense, the re-turn to holism is an understanding of the self as part of a thoroughly connected whole.