Chapter 1 begins to define the concept of social pathology and to assess its usefulness for social philosophy. It distinguishes five conceptions of social illness different from the one employed in this book, which places dysfunction, rather than suffering, at the core of social illness. It argues, further, that while social pathologies must be bad in some way for social members, those individuals are not typically ill themselves. Although there are good reasons for approaching the concept of social pathology with caution – societies differ in important ways from biological organisms, for example – judicious use of the concept can bring to light critique-worthy social phenomena to which theories focused exclusively on justice are blind. The method espoused for diagnosing social illnesses is a form of ethically informed immanent critique that bears some similarities to medical diagnosis but refrains from ascribing moral blame to the individual participants in unhealthy social practices.