The detective stories written by Arthur Conan Doyle featuring his legendary protagonist Sherlock Holmes have been read by many millions of readers. Fairly early in Holmes’ literary life, Doyle became tired of writing these stories and decided to kill off his popular hero; but, after a seemingly fatal struggle against his nemesis, the evil Professor Moriarty, the public outcry persuaded him to bring Holmes miraculously back to life. Even though Sherlock Holmes never married or had children, he has spawned a legion of detective offspring, including Father Brown, Hercule Poirot, Jane Marple, Peter Wimsey, Inspector Maigret, Nero Wolfe, Philip Marlowe, and Lew Archer, as well as child detectives like Nancy Drew and Encyclopedia Brown, who are all, without exception, unerring masters of deductive reasoning.

Of course, those who read these stories know that they are fictional inventions of their authors, and that they do not necessarily correspond to real life; but there are many instances of fiction, whether literary, theatrical, cinematic, photographic, or otherwise, influencing or determining people’s behaviours, beliefs, or expectations about the real world. For example, when Goethe’s The Sorrows of Young Werther was first published, the novel was banned in several countries because it led a number of young readers to commit suicide, in imitation of the novel’s protagonist. Those who read or watch depictions of romantic courtships that end with the couple living happily ever after are not at all prepared for the numerous arguments, disputes, and disagreements that characterize most real-life relationships. The frequent depictions of violence in movies and television programs occasionally motivate some viewers of these fictional episodes to imitate what they see the actors doing on the screen. And the recent spread of pornography in Western societies has had a strong influence in changing people’s sexual and courtship behaviour, including the imitation of sexual practices that were formerly rare or were considered highly aberrant.

According to the Theory of Imitation, the models of behaviour that a person observes, whether they are real or fictional, can influence one’s behaviour, beliefs, and expectations. For example, it is known that fashion trends or certain expressions that are seen or heard in a movie or television program can become widely imitated in real life. What, then, is the model of behaviour that is repeatedly depicted in detective stories like those written by Arthur Conan Doyle and his many successors? Very simply, it is the model of a human being who uses one’s reasoning powers to arrive unerringly at the truth, in order to solve a mystery or apprehend the perpetrator of a criminal act. In other words, unless it is corrected in some way, reading these stories will lead readers to believe that, properly employed, reason and logic are infallible guides to discovering the truth about the world we live in.

I doubt there is anyone who would rank Arthur Conan Doyle’s fictional invention as one of the great rationalists of all time. And yet, in terms of popular influence, I believe that Sherlock Holmes has done as much, if not more, to spread the pernicious faith in the magical, truth-discovering powers of reason and logic as important rationalist philosophers like Descartes, Leibnitz, Spinoza, and their ancient predecessors Aristotle and Plato. For how else can we account for the fact that there are still a great many people, including many highly-educated adults, who believe in this falsehood, despite the innumerable real-world proofs to the contrary, which show that reason and logic are extremely fallible and erring guides to discovering the truth about the real world? Anyone who naively believes that reason and logic are unerring guides to the truth will make numerous blunders in the course of one’s life, whether personally or professionally.

For the sake of balance and accuracy, specifically to disabuse his readers of their faith in reason’s unerring judgment, it would have been well if Doyle had written some stories in which Holmes’ deductive processes lead him to the wrong conclusion, or to suspect the wrong person, both of which outcomes occur quite often in the real world that we live in. Numerous are the real-life instances in which a police or criminal investigation leads to the arrest or conviction of the wrong person, to ambivalent or inconclusive results, and to unsolved crimes. The fact that Holmes almost never makes a mistake in his reasoning in any of his cases – or even if he does, he always manages to detect and correct his mistake in the end – is just as absurd and impossible as the depiction of flying human beings like Superman. But because these things are not obviously false, as the depiction of flying human creatures is, they have had the pernicious effect of making many readers naively trust the superhuman powers of reason and logic. By doing so, they have disseminated the falsehood that, properly employed, reason and logic endow their users with the superhuman trait of infallibility, which no human being has ever possessed, and never will possess.