Before I begin to show specifically how what I have been calling the modern dominant model of moral philosophy excludes certain forms of philosophical writing, as well as the loss to our philosophical endeavors that would accompany such an exclusion, I want to demonstrate a simpler point. I want to question the foundational assumption that a sustained philosophical thesis or argument can only take place within certain types of form such as the treatise or essay. I do this through a questioning of its corollary that a work that does not take this type of “philosophical” form cannot be a sustained work of philosophy. Perhaps at best, this corollary continues, this type of work can offer a few philosophical insights. In this way, therefore, this chapter is somewhat different from the other chapters in the book, as my focus is on the expectations of its philosophical content produced by the epistolary form of Catharine Macaulay’s work Letters on Education. Indeed at the risk of belaboring my point, I spend time in the introductory pages to this chapter giving a lengthy overview of modern commentaries on Macaulay’s work, analyzing and, at times, speculating about the assumptions that drive their interpretations.