Can we say that "The Red-Headed League" is a manichean text?
Manichaeism is a philosophy of dualities: the existence of good and evil principles with good relating to mind and the spiritual and evil relating to matter and the material. When this philosophical position is applied to literature, the text sets up these dualities of good/spirituality/light opposing evil/materialism/darkness. In "The Red-headed League" it can be said that these two positions do oppose each other in the text. John Clay and Duncan Ross, his associate, are the representations of evil. They manipulate others for their own end. They have large scale plans for destructive actions. Their work lies in the dark with material things (i.e., tunneling through earth) and has as its end aim only material objects (i.e., material wealth from the bank). On the other hand, it can be said that Sherlock Holmes and John Watson are the representations of good. They uncover nefarious schemes for the purpose of protecting of the innocent. They devise large scale plans for implementing redeeming actions. Their work lies in the light. Their tool is the mental (i.e., reasoning deduction) and has as its object the aim of outsmarting those who are doing evil. In this sense, according to this outline, "The Red-Headed League" might be called a manichean text.