In this essay, and in honor of physician-philosopher H. Tristram Engelhardt, Jr.'s contributions to bioethics and philosophy of medicine, I argue that what makes Engelhardt's body of work notable in the history of philosophy is his recognition that medical concepts, such as disease and health, illustrate the dependence of bioethics and philosophy of medicine on each other. In what follows, I review Engelhardt's analysis of disease in terms of its descriptive, explanatory, evaluative, and social dimensions. I show how the concept of disease carries bioethical implications, and such bioethical implications are framed in terms of ontological and epistemological considerations made explicit in the philosophy of medicine, thus highlighting the reliance of bioethics on philosophy of medicine, and vice versa.