Hall describes The Well of Loneliness as "The first long and very serious novel entirely upon the subject of sexual inversion".[57] She wrote The Well of Loneliness in part to popularise the ideas of sexologists such as Richard von Krafft-Ebing and Havelock Ellis, who regarded homosexuality as an inborn and unalterable trait: congenital sexual inversion.[58]
In Krafft-Ebing's Psychopathia Sexualis (1886), the first book Stephen finds in her father's study, inversion is described as a degenerative disorder common in families with histories of mental illness.[59] Exposure to these ideas leads Stephen to describe herself and other inverts as "hideously maimed and ugly".[60] Later texts such as Sexual Inversion (1896) by Havelock Ellis – who contributed a foreword to The Well – described inversion simply as a difference, not as a defect. By 1901 Krafft-Ebing had adopted a similar view.[61] Hall championed their ideas over those of the psychoanalysts, who saw homosexuality as a form of arrested psychological development, and some of whom believed it could be changed.[62] Indeed, Havelock Ellis' commentary for the novel, which, although edited and censored to some extent, aligns the novel directly with theories of sexual inversion: "I have read The Well of Loneliness with great interest because—apart from its fine qualities as a novel by a writer of accomplished art—it possesses a notable psychological and sociological significance. So far as I know, it is the first English novel which presents, in a completely faithful and uncompromising form, one particular aspect of sexual life as it exists among us today. The relation of certain people, who, while different from their fellow human beings, are sometimes of the highest character and the finest aptitudes—to the often hostile society in which they move, presents difficult and still unresolved problems".[63]
The term sexual inversion implied gender role reversal. Female inverts were, to a greater or lesser degree, inclined to traditionally male pursuits and dress;[64] according to Krafft-Ebing, they had a "masculine soul". Krafft-Ebing believed that the most extreme inverts also exhibited reversal of secondary sex characteristics; Ellis's research had not demonstrated any such physical differences, but he devoted a great deal of study to the search for them.[65] The idea appears in The Well in Stephen's unusual proportions at birth and in the scene set at Valerie Seymour's salon, where "the timbre of a voice, the build of an ankle, the texture of a hand" reveals the inversion of the guests.[66][67]
