The following post is the contribution of current MEST graduate student, Meagan Allen. Meagan is a doctoral candidate in the Department of History and Philosophy of Science and Medicine at Indiana University and a Cain Dissertation Fellow at the Science History Institute in Philadelphia, PA. Her dissertation, “Roger Bacon’s Medical Alchemy: Occult Remedies and the Prolongatio Vitae,” explores the relationship between 13th-century medical theories and Roger Bacon’s ideas about the ability of alchemy to prolong human life.
Many aspects of the medieval world seem so different from our own, especially for the student engaging with medieval sources for the first time. This is especially difficult when teaching the history of premodern science: as the concept of scientia has changed over the centuries, topics that today would be considered pseudo-science must be incorporated into our classes, much to the confusion of some students.

My own research focuses on one of those great pseudo-sciences, alchemy. For many, the word alchemy conjures images of scam artists, knowingly defrauding others with gold replicas, or worse, sorcerers circumventing the laws of nature with their magical philosophers’ stone. When I teach or engage in science outreach, the most common question I get asked is “why did people believe in alchemy?”
For anyone even generally acquainted with the principles of modern chemistry, it can be difficult to understand how alchemy as a scientific theory stayed relevant for so many centuries. Everyone knows that outside of the realm of fantasies like Harry Potter and Fullmetal Alchemist, there is no philosophers’ stone, no secret recipe than can change lead into gold, and no elixir that can prolong human life.
I can explain that for most medieval alchemists, ‘alchemy’ was just the method of understanding nature’s processes so that artisans could improve upon them—more proto-chemistry than magic—but that only goes so far. How can we help students better understand medieval science on its own terms? In this case, seeing really is believing. While explaining premodern chemical theories helps, nothing proves the believability of alchemy like a demonstration.
My favorite demonstration is a “transmutation” of one metal into another. When a high-carbon steel sawblade is dipped into a solution of copper sulfate, the blade is plated with a thin layer of copper. This change is instant, and it really appears that the steel has changed into copper. The thin layer of copper can then be sanded off, once again revealing the steel.

After performing this “transmutation”, I ask the students to imagine that they have never heard of the periodic table of elements, reactivity of metals, or any other 21st century chemistry. By seeing how a “transmutation” can occur, students can better understand the enduring explanative power of alchemy. Rather than being nonsense or bad science, they become viable explanations for the natural world that used the best technology available, even if they are considered outdated today and have been replaced by other theories.