Sherlock Holmes the character was also an author. Like some of Poe's disquisitions on the logic behind the character of Dupin, the analysis of analysis is more alive that the detective genre can ever allow. This in part helps explain why Hammett refuses its conceits and created his own. In the case of Holmes, his writing on what of life there is, through the coal dust of London, to be detected is far more interesting than the strange and foreign riddles portrayed.
His method is described by way of an anonymous article he pens, which Watson reads almost as an introduction to him. It is called "The Book of Life." There he describes the infinite task of careful appraisal that renders the system of the world as legible as Galileo imagined the heavens to be.
In this, if only this, he sounds like an anthropologist who believes that culture is nothing less than the "the order of the symbolic" and that in the creative exercise of that symbolic material, culture is made and remade, sustained in its perpetual, baseless, and communicable expression.
"Let the inquirer . . . learn at a glance to distinguish the history of the man, and the trade and profession to which he belongs. . . . By a man's finger-tips, by his coat sleeve, by his boots, by his trouser-knees, by the callosities of his fore-finger and thumb, by his expression, by his short-cuffs--by each of these things a man's calling is plainly revealed."--A. Conan Doyle, A Study in Scarlet