• Sixteenth-century natural philosophers and physicians crafted novel ideas on bodies and their internal powers. Their theories often went far beyond the framework of the traditional Aristotelian perspective, influencing the broader philosophical scene of the sixteenth and early seventeenth centuries. Although the principal actors in Renaissance natural philosophy had a variety of motivations and points of departure, many of them were medically educated humanists or humanistically trained physicians. This was the case, for example, of Jean Fernel, Girolamo Cardano and Julius Caesar Scaliger. Under the influence of these figures, eminent writers such as Bernardino Telesio and Justus Lipsius, though not educated as physicians, took pains to engage in discussions of the natural world. Their writings exerted a considerable impact on later generations.

    Contents
    1. Natural Philosophy, Medicine and Alchemy
    1-1. Medicine
    1-2. Alchemy/Chymistry
    2. The Formative and Plastic Power of the Seed
    2-1. Galen’s Idea Revived
    2-2. The Seed’s Celestial Force
    2-3. The Plastic Faculty as God’s Invisible Hand
    2-4. Toward Plastic Nature
    3. Spirits, Cosmic Heat and the Principle of Life
    3-1. Spirits and Their Celestial Origin
    3-2. Cosmic Heat and the World-Soul
    3-3. The Spirit as the Material Crystallization of Cosmic Heat
    4. Seeds and the Seminal Principle
    4-1. Ubiquity of Invisible Seeds in Nature
    4-2. The Christianization of Cosmic Heat
    4-3. A Synthesis as a the Philosophy of Seeds
    – References