Sir

Richard Gregory, in Books & Arts, is not the only one to find professional inspiration in Arthur Conan Doyle's fictional hero Sherlock Holmes (“The great detective” Nature 445, 152; 2006).

See, for example, the work of Umberto Eco and Thomas A. Sebeok, comparing the reasoning methods of Holmes and of Edgar Allan Poe's detective, C. Auguste Dupin, with those of the logician Charles Peirce, in The Sign of Three: Dupin, Holmes, Peirce (Advances in Semiotics) (U. Eco and T. A. Sebeok, Indiana Univ. Press, 1984).

One might wish to follow Holmes's example with caution, however. As ably documented by Dr Watson in A Study in Scarlet, Holmes's scientific credentials are mixed. Watson's note, headed “Sherlock Holmes: his limits”, includes:

“[knowledge of] Astronomy: nil... Botany: variable. Well up in belladonna, opium, and poisons generally. Knows nothing of practical gardening. Knowledge of geology: practical, but limited. Tells at a glance different soils from each other. After walks has shown me splashes upon his trousers, and told me by their colour and consistence in what part of London he had received them. Knowledge of chemistry: profound... Anatomy: accurate, but unsystematic.”

Famously, despite referring to his methods as “the science of deduction and analysis”, Holmes was unable to distinguish between a deductive and an inductive inference. This failing might be accounted for by the fact that Watson also documented Holmes's knowledge of philosophy as “nil”.