Philosophical Letters (1664)

Philosophical Letters or Modest Reflections Upon Some Opinions in Natural Philosophy, referred to simply as Philosophical Letters, published in 1664, is a series of critiques authored by Margaret Cavendish, Duchess of Newcastle-upon-Tyne in which she examines the writings of other highly notable 17th Century philosophers. This is Cavendish’s first work in which she takes issue with the writings of other philosophers. She specifically examines the writings of Rene Descartes, Henry More, J.B. van Helmont, and Thomas Hobbes. In Familiar Epistolary Philosophy: Margaret Cavendish’s Philosophical Letters (1664), Diana Barnes asserts that “Although Cavendish was well read in philosophy she was not well trained in its modes of argumentation and proof” (1). Nevertheless, Cavendish confidently presents herself as being among peers in discussing the works of other philosophers. The Philosophical Letters are framed as personal letters written to an unnamed, female friend referenced only as “Madam.” According to Barnes, the epistolary discourse casts the work into a metanarrative in which, contrary to the prevailing thought of its day, serves to instantiate Cavendish’s conviction that “rational feminine exchange” is reflected in its content. Furthermore, an epistolary format assists Cavendish to fulfill a promise made to her husband, the Duke of Newcastle in the opening pages of Philosophical Letters, that she will not “make Enemies of Friends” as she takes issue with the writings of other philosophers.

Considerable scholarship has accumulated in the early 21st Century around Cavendish’s work. In Leviathan and the Lady: Cavendish’s Critique of Hobbes in the Philosophical Letters, Lisa T. Sarasohn states that “Cavendish counters Hobbe’s mechanistic materialism with her theory of self-determining materialism and does so through the letter, a formal, polemical means of argumentation. Stephen Clucas of the University of London laments the fact that Cavendish’s critique of Van Helmont in the Philosophical Letters is noticeably absent from scholarship. In Margaret Cavendish’s Materialist Critique of Van Helmontian Chymistry, Clucas compares her writings to those of Robert Boyle in that both critics attack Van Helmont’s obscure terminology and “seminalism.” In Margaret Cavendish’s Socio-Political Interventions into Descartes’ Philosophy, Erin Webster states “that Cavendish’s critique of Descartes’ dualism, like her critique of atomism, is structured along not only physical but also political lines” (3). Furthermore, Webster asserts that Cavendish argues that “the mind cannot be separated from either the body or the external world” (711). Taken together, her critiques of other 17th Century philosophers are conducted in an epistolary manner to expose her belief that the mind and the human individual cannot be separated from community in particular or the external world in general. Philosophical Letters also details Cavendish’s opposition to Henry More’s belief in immaterial substance.

In the preface to Philosophical Letters, Cavendish declares herself to be “so uncapable of learning” and confounds contemporary attempts to confidently assert either feminist or proto-feminist leanings. Perhaps her self-debasing comments can be cast into the social expectations of the 17th Century, when women scarcely ventured beyond household subjects for fear of the effrontery they might present to male pedantry. By willing to offer counterpoints to the views of highly established philosophers, all male, Cavendish already portrays the stamina to gain scholarly attention. By investing thoughtful reflections into texts such as Philosophical Letters, she has earned the right to attract such attention for many years to come.


Barry Cole


Works Cited

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Fitzmaurice, James. “Cavendish , Margaret, duchess of Newcastle upon Tyne (1623?–1673).”

James FitzmauriceOxford Dictionary of National Biography. Online ed. Ed. Lawrence

Goldman. Oxford: OUP, . 15 Sept. 2014


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Several Famous And Learned Authors Of This Age, Expressed By Way Of Letters / By

The Thrice Noble, Illustrious, And Excellent Princess The Lady Marchioness Of

Newcastle. n.p.: London : [s.n.] 1664., 1664. University of Alabama Libraries’ Classic

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Sarasohn, Lisa T. “Leviathan And The Lady: Cavendish’s Critique Of Hobbes In The

Philosophical Letters.” Authorial Conquests: Essays on Genre in the Writings of

Margaret Cavendish. 40-58. Madison, NJ; London, England: Fairleigh Dickinson UP;

Associated UP, 2003. MLA International Bibliography. Web. 14 Sept. 2014.

Webster, E. “Margaret Cavendish’s Socio-Political Interventions Into Descartes’ Philosophy.”

English Studies 92.7 (2011): 711-728. Scopus®. Web. 14 Sept. 2014.