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Department of History and Philosophy of Science


Research Project

The Doctrine of Signatures in Early Modern Medical Practice

Supervisors: Dániel Margócsy, Lauren Kassell

A walnut looks like a brain, and therefore could cure brain diseases — in pharmaceutical science and natural remedies today, a traditional medicinal idea “doctrine of signatures” is widely cited, which holds that plants’ morphological resemblance to human organs indicate their curative effects. While this doctrine was often described as an ancient, traditional and even pre-historical idea, it was only first conceptualised as a full-blown theory by Swiss physician Paracelsus and gained its name, the “doctrine of signatures (Signaturenlehre),” from Paracelsus and theologian Jakob Böhme. From the historical introduction of John Ayrton Paris's Pharmacologia (1822) to Philippe Descola’s “Analogical Ontology” (2013 [2005]), the doctrine of signatures has been constantly constructed as a premodern paradigm of thoughts that connected plants, animals and men with analogies, in opposition to any scientific world view. Today in historical scholarship, the doctrine of signatures has been frequently mentioned as a medical philosophy, an emblematic world view or allegorical reading of nature; yet it has not been systematically examined in early modern therapeutic practices, from chymical laboratories to household recipes. Meanwhile, despite being famously rejected by some influential scientists such as John Ray, this doctrine’s persistent influence on late seventeenth-century botanical and medical sciences has often been undermined.

This project aims to penetrate layers of myths concerning the doctrine of signatures, and historicise this doctrine in practices of early modern alchemy, medicine and natural history. It primarily focuses on German-speaking areas and England in the sixteenth and seventeenth century, while taking the broader temporal and geographical scale into consideration. It will challenge the treatment of this doctrine as a monolithic cosmology, and instead approach it as a fluid, malleable set of ideas and practices developed and transformed throughout the time. In the first chapter, it will present an “archaeology” of the invention of our common conception of the doctrine of signatures today, following a reversed timeline from nineteenth-century colonial medicine to the "survival of antiquity" in Renaissance. In the second chapter, it will examine the doctrine of signatures against the dynamics between pathologies and therapeutics in medical practitioners from Paracelsian chymists to household recipe authors. In the third chapter, it will identify the influence of this doctrine in late seventeenth-century sciences from microscopy to plant physiology, and discuss its Janus face as both science and superstition.

Grants And Fellowships

Visiting Scholar, Department of History and Civilisation, European University Institute, Spring 2022.

Wellcome Trust Doctoral Studentship in Humanities and Social Science, 2020.

Public Lectures

The Doctrine of Signatures in Early Modern Medicine,” available on YouTube. British Society for the History of Pharmacy, 25 April 2022.

“The Doctrine of Signatures: A Curious History,” Cambridge Festival, 5 April 2022.

Selected Conference Talks

“The Lesser Herbals in Late Seventeenth-Century England,” RSA Annual Meeting 2022, 31 March 2022.

"Lines and Grids: The Cosmological Taxonomy of Margaret Boscawen’s Herbal Notebooks," AHA Annual Meeting 2022 (Online), 21 February 2022.

"Bilderfahrzeuge to China: Aby Warburg’s Encounter with Chinese Astrology,” The Making of the Humanities IX Conference, Barcelona, 20 September 2021.

"When Jupiter Meets Saturn: Aby Warburg, Karl Sudhoff, and Astrological Medicine in the Age of Disenchantment,” in "Emotional Objects: Northern Renaissance Afterlives in Object, Image and Word, 1890s - 1920s," Warburg Institute, 23 April 2021.


Xinyi Wen is a PhD candidate at Department of History and Philosophy of Science, University of Cambridge. She is currently working on research project ‘The Doctrine of Signatures in Early Modern Medical Practice (Wellcome Trust 221115/Z/20/Z)’. Her project approaches questions concerning Renaissance analogical worldview and early modern magic-science transition from the perspective of medical practice, and pays particular attention to the temporalities behind our conventional image of ‘the doctrine of signatures’ today. Her research interest covers multiple disciplines of early modern knowledge, including medicine, chymistry, natural history and philosophy. In addition to the early modern era, she also studies twentieth-century intellectual history, particularly in the circle of art historian Aby Warburg (1866-1929), and has a broad interest in anthropology, media theories and contemporary philosophy. 

Before coming to Cambridge, Wen has been a curator and researcher of contemporary art in Beijing. She has worked as convenor of New Media Research Group at Center for Visual Studies, Peking University, and has published several journal articles and reviews on contemporary art, media theories, and laboratories in art and science. She holds a BPhil in philosophy and classical studies from Peking University, and an MPhil in history of science from Cambridge.


Early modern science and medicine; natural history; alchemy; astrology; recipes; Aby Warburg.

Teaching and Supervisions


Part II Paper 1: Early Science and Medicine

Postgraduate And Postdoc Training Seminar: Introduction to Data Management and Digital Humanities

Other Professional Activities

Xinyi Wen is a Cambridge Data Champion and she provides training and advices in research data management and digital humanities. She is also the founder of the History of Science Library, a public Zotero library for history of science and a resource hub for data management in humanities.

PhD Candidate
In a hall of Casa Vasari, Arezzo, a black-hair female in glasses and caramel coat is sitting in front of the window and reading on an ebook reader


Collaborator profiles: