One of the best-known principles of halakha is that Shabbat is violated to save a life. Who does this saving and how do we know that a life is in danger? What categories of illness violate Shabbat and who decides? A historical-sociological analysis of the roles played by Jew, non-Jew, and physician according to the approach of “medical cosmology” can help us understand the differences in the approach of the Shulchan Aruch compared to later decisors (e.g., the Mishnah (...) Berurah). Such differences illuminate how premodern medical triage coexisted with a different halakhic understanding than that of the biomedical age. (shrink)