This thesis is an investigation into ways of seeing 12 Step fellowships. The latter provide a popular but controversial means of recovery from various addictive behaviours. The conceptual basis of 12 Step fellowships is the idea that addictions are an illness or disease, and this idea has become the focus of the negative critiques of 12 Step fellowships. Concepts of illness and disease are closely related to concepts of personhood. What 12 Step discourses construct as 'illness' can also be understood as a condition characterised by failure of human capacities for agency, choice, and responsibility. How we understand 12 Step discourses of addiction, illness, and recovery will depend greatly upon the concepts of personhood, illness, and knowledge that inform our view. In order to investigate the concepts that make diverging views of 12 Step fellowships possible, this study develops post-Enlightenment concepts of personhood, illness and knowledge. I use these concepts as a lens with which to examine the negative critiques, and to provide a more positive reading of 12 Step fellowships and illness concepts. In doing so, this thesis aims to show, first, that a positive view that can articulate the value of 12 Step fellowships to 12 Step members is possible, and second, that 12 Step fellowship discourses are philosophically interesting and challenge modern western notions of the self and its capacities. The thesis has six chapters. Chapter One presents an overview of the study, and introduces the basic concepts and practices of 12 Step fellowships. Chapter Two presents an epistemology called perspectivism which provides my research methodology as well as a means of analysing the epistemological assumptions at work in the negative critiques of 12 Step discourses. In order to understand how the capacities of the self may fail, and how such failures might be remedied, Chapter Three presents a post-Enlightenment theorisation of personhood as constituted, embodied, and socially embedded subjectivity. This theorisation enables us to examine how embodied selves may be constituted with diminished capacities for agency, responsibility, and choice, and permits the construction of an account of addiction that explains why addictive disorders are a significant social problem in contemporary western societies. Finally, this theorisation enables us to investigate the concepts of personhood that inform the negative critiques. Chapter Four investigates how concepts of illness inform the negative critiques, and shows that it is possible to understand terms such as 'illness' and 'disease' in a non-medical sense. Arguably, such understandings are better able to illuminate the connection between the notion of illness and recovery practices in 12 Step discourses of addiction. Chapter Five uses the conceptual framework provided by Chapters Two, Three, and Four to present a positive view of 12 Step fellowships and discourses. The three key features of this view are, first, that 12 Step fellowship discourses describe addictions as an illness of the self; second, they provide a phenomenology of the sick self; and third, 12 Step recovery discourses and practices are consistent with the notion that the constituted self is limited, and can be reconstituted or changed through practice of the 12 Step recovery program. Together, these three key features show us that 12 Step fellowships provide a valuable social resource for people with limited capacities for self-regulation to help themselves and each other. Chapter Six considers the implications of this more positive view of 12 Step fellowships in terms of the primary and secondary aims of this thesis.