This dissertation is about the way people _should_ and _do_ make medical choices. It defends the claim that medical decisions should be made by groups of persons acting together, not by individuals acting alone. I begin by arguing that prominent models of medical decision-making are problematic, because they fail to be both _descriptively_ and _normatively_ adequate, which I argue any account of choice in medicine should be. The remainder of the work articulates a model that meets these two criteria. First, I justify an account of the uniquely medical context my model is designed to apply to by distinguishing _two basic aims of medicine:_ (i) to fully understand patients in personal and scientific terms; and, (ii) to intervene upon patients' health states in ways that are consistent with this understanding. Then, I take two chapters to develop a descriptive account of medical decision-making. In them, I introduce a close study of the case of hereditary breast and ovarian cancer decision-making, which I argue shows choices are made by groups of interacting persons over extended spatiotemporal and social dimensions. So, I appeal to the theory of _distributed cognition_ to describe this collection of persons processing information together when making choices. Having defended a descriptive account of medical choice, I then take two more chapters to propose a normative account, based on a modified version of Rawlsian reflective equilibrium that I call _medical reflective equilibrium._ On my account, medical choices should be made by searching for, selecting, and integrating the right kind and amount of information, which requires considering sufficient information to meet the basic aims of medicine. Given that the basic aims are defined in terms of an epistemic distinction between _subjective_ and _objective_ knowledge, I argue that performing the medical reflective equilibrium procedure adequately requires multiple participants in decision-making. Consequently, I conclude that medical choices are and should be social
