ABSTRACT
Positivism in the history of science and medicine was challenged by Walter Pagel more than fifty years ago. He sought to understand early modern figures such as Harvey, Paracelsus, and van Helmont by looking at all their work, including nonscientific material generally ignored by other scholars. Of special importance in the sixteenth and seventeenth centuries was the chemistry found in the writings of Paracelsus and his followers. These "chemical philosophers" offered a new philosophy based on chemistry and chemical analogies that was to replace the works of the ancients. As physicians, they debated first with Galenists and Aristotelians and later with mechanists. The essay argues that these debates were an essential chapter in the development of the Scientific Revolution and important for understanding the Chemical Revolution of the eighteenth century.
