Edinburgh Napier University

  This thesis examines the meaning, origin and influence of Edgar Allan Poe’s notion of the ‘Bi-Part Soul’, and the associated theme of duality, in selected texts of nineteenth-century detective fiction. Poe’s detective opus, ‘The Murders in the Rue Morgue’ (1841), ‘The Mystery of Marie Rogêt’ (1842) and ‘The Purloined Letter’ (1844), features the eccentric and complex Monsieur C. Auguste Dupin and establishes Poe as a significant pioneer in the cultural genesis of the detective genre. Poe’s idea of a ‘double’ detective with a ‘Bi-Part Soul’, who is both ‘creative and resolvent’ but also exhibits a ‘diseased intelligence’, provides a compelling psychological ‘blueprint’ for subsequent fictional detectives.

The meaning of the ‘Bi-Part Soul’ and how it relates to Poe’s divergent philosophical beliefs of Transcendental Idealism and Materialism are evaluated before establishing a strong connection between the ‘Bi-Part Soul’ and a more general notion of duality, manifested in the literary motifs of doubling, the divided self and the doppelgänger. This is followed by a discussion of the origins of the ‘Bi-Part Soul’. The thesis argues that its derivation can be found in Aristotle’s (384 – 322 BC) bipartite psychology which reflects the same split between the rational and irrational human virtues. The explication of the tropes which evolve from ‘The Bi-Part Soul’ are explored in a Case Study focusing on ‘The Murders in the Rue Morgue’ (1841).

The presence and influence of ‘The Bi-Part Soul’ and duality in British nineteenth-century fiction, which acts as a prologue to the conception of the detective genre, are examined in the context of the Newgate novel and Sensation fiction (1830 – 1868), Charles Dickens’ Bleak House (1853), Wilkie Collins’ The Moonstone (1868) and Robert Louis Stevenson’s Strange Case of Dr Jekyll and Mr Hyde (1886). Dupin’s ‘Bi-Part’ psychological mould is traced throughout the fictional detectives in these texts and culminates in an analysis of Arthur Conan Doyle’s fin-de-siècle Sherlock Holmes. This dissertation suggests that Poe’s notion of the ‘Bi-Part Soul’ established an enduring and influential model for subsequent writers of detective fiction and continues to shape the culture of the genre to this day.