This chapter uses three secondhand reports (the testimonies on Petron and Philistion in the Anonymus Londiniensis, the speech of Eryximachus in Plato’s Symposium, and the treatise On Ancient Medicine) to point out that an interest in cosmological principles does not preclude more traditional explanations of health and disease. Petron, Philistion, and Eryximachus all combine their first principles with lower-level discussions of the humors, pneuma, and the “powers” of food and drink. Instead of replacing humors with cosmic principles, these doctors constructed multitiered narratives of pathogenesis, placing humors and cosmic principles at different points in the causal chain. After making this point, this chapter then demonstrates that the polemical On Ancient Medicine is an unreliable witness to what the cosmological doctors were doing. Whereas the author of this text claims that the prioritizing of such principles as the hot and the cold is incompatible with the attribution of diseases to the humors, the cosmological doctors were in fact more than comfortable with combining first principles with more traditional beliefs about the body.