Secrets, Lies, and Hands with Eyes: Daniel Sennert on Openness and Fraud in Chymistry and Chymical Medicine

Abstract This paper examines the themes of secrecy, deception, and openness in early modern chymistry and medicine, focusing on episodes from the correspondence of the prominent German physician and natural philosopher Daniel Sennert. It highlights how Sennert and his brother-in-law, the Breslau municipal physician Michael Döring, confronted a culture rife with fraudulent claims and secretive practices that were especially prevalent amid the economic and political instability that prevailed during the Thirty Years’ War. The paper reveals their struggles against the charlatanism of those who sought to exploit the chaotic medical marketplace of the time, and the analysis extends to the broader implications of their advocacy for transparency that drew upon humanist literature and Christian religious ideals. This work positions Sennert as an archetypical figure in the transition towards skepticism and openness in science, highlighting the significant role of German chymical physicians in shaping early modern scientific discourse.