Holmes is often portrayed as a mechanical logician, but his approach depends more on outside-the-box thinking that, according to modern research, really does help solve problems.
When most people think of Sherlock Holmes, they see a paragon of calculating logic: a chilly, computer-like machine with endless powers of reason. As the UK's Telegraph put it, "If Holmes is not cold, inhumanly calculating ... he's just not Holmes"—echoing the words of such prior Holmesians as David Grann, who wrote in The Devil and Sherlock Holmes that "Holmes is a cold, calculating machine, a man who is, as one critic put it, 'a tracker, a hunter-down, a combination of bloodhound, pointer, and bull-dog." Even Holmes's creator, Arthur Conan Doyle, tried to dismiss him as "inhuman as a Babbage's calculating machine" when he tired of his creation, just a year before he tried to kill him off entirely in "The Final Problem." But in reality, that perception is far from the truth. In working on my new book Mastermind: How to Think Like Sherlock Holmes, it occurred to me that what allows the detective to attain the heights of deduction that he does is the very thing a computer lacks entirely: the power of imagination.
Consider: When Sherlock Holmes is asked to investigate a mysterious death on the shores of a small village in Sussex, he realizes that the cold-blooded, vicious murderer—the victim has terrible weals all along his back, "as though he had been terribly flogged"—is not exactly of the human variety. While the police focus their efforts on Ian Murdoch, a competitor for the affections of the dead man's fiancée, Holmes follows instead a lead of a different sort: the dead man's last words, "lion's mane." Those words, in turn, lead him to the real killer, none other than a deadly jellyfish.