Charles writes about skepticism in contemporary philosophy and the Early Modern Period, with a focus on the writings of David Hume and Immanuel Kant.  His other research interests include the history of medicine, physiology and psychology and its role in the development of Early Modern thought, especially during the Scottish Enlightenment.

His essay "The Humors in Hume's Skepticism" received the 2019 Early Modern Worlds Biennial Graduate Student Prize.  In it, Charles argues that Hume invokes the humors of ancient and medieval medicine throughout his discussion of skeptical melancholy in theTreatise of Human Nature.  Understanding Hume's intent in employing these medical tropes, Charles explains, reveals what Hume thinks skepticism is, and what role he thinks it should play in human life.

More information can be found at Charles' personal website.