The author's thesis is that during the mid-20th century, an intellectual shift toward scientific notions of care challenged the nursing profession's oldest practice values grounded in religious ideas of suffering and compassion. The author uncovers the vacillation between the expression of dominant scientific and rival compassionate ideas in the published and unpublished nursing literature of the 1950s. The evidence is first placed in a historical context of 20th century nursing history, explaining why the profession emphasized scientific approaches to care following World War II. The evidence is then placed into two larger contexts: (a) that of the greater body of scientific and humanistic writing during the period showing concern about the applications of science and technology and its moral implications, and (b) the context of early to mid-20th century notions of "positivism," highlighting the relationship between empirical knowledge and moral ideas that orient human actions. The article concludes with an analysis of implications for nursing practice.