This episode explores different interpretations of the word "is," particularly within the context of medieval philosophy and logic. The conversation begins with an overview of three competing schools of thought: the copulative theory, the aspect theory, and the substantive verb theory. Against the backdrop of modern logic, which largely adheres to the copulative theory, the discussion pivots to the aspect theory, influenced by Arabic grammar and Avicenna's work, highlighting its unique approach to predication. More significantly, the episode introduces the substantive verb theory, rooted in medieval grammar and the work of Priscian, which posits that "is" signifies essence or substance. As the discussion progresses, the conversation analyzes the advantages and disadvantages of each theory, particularly in relation to interpreting Aristotle and Aquinas. The episode concludes by considering the implications of these different interpretations for understanding key metaphysical concepts, such as the real distinction between essence and existence, and for appreciating the historical development of Thomistic thought.
