Mastermind: How to Think Like Sherlock Holmes
In the spring of 1907, Edalji was finally cleared of the charge of animal slaughter. It was less than the complete victory for which Conan Doyle had hoped—George was not entitled to any compensation for his arrest and jail time—but it was something. Edalji was readmitted to his legal practice. The Committee of Inquiry found, as summarized by Conan Doyle, that “the police commenced and carried on their investigations, not for the purpose of finding out who was the guilty party, but for the purpose of finding evidence against Edalji, who they were already sure was the guilty man.” And in August of that year, England saw the creation of its first court of appeals, to deal with future miscarriages of justice in a more systematic fashion. The Edalji case was widely considered one of the main impetuses behind its creation.
Conan Doyle’s friends were impressed. None, however, hit the nail on the head quite so much as the novelist George Meredith. “I shall not mention the name which must have become wearisome to your ears,” Meredith told Conan Doyle, “but the creator of the marvellous Amateur Detective has shown what he can do in the life of breath.” Sherlock Holmes might have been fiction, but his rigorous approach to thought was very real indeed. If properly applied, his methods could leap off the page and result in tangible, positive changes—and they could, too, go far beyond the world of crime.
Say the name Sherlock Holmes, and doubtless, any number of images will come to mind. The pipe. The deerstalker. The cloak. The violin. The hawklike profile. Perhaps William Gillette or Basil Rathbone or Jeremy Brett or any number of the luminaries who have, over the years, taken up Holmes’s mantle, including the current portrayals by Benedict Cumberbatch and Robert Downey, Jr. Whatever the pictures your mind brings up, I would venture to guess that the word psychologist isn’t one of them. And yet, perhaps it’s time that it was.
Holmes was a detective second to none, it is true. But his insights into the human mind rival his greatest feats of criminal justice. What Sherlock Holmes offers isn’t just a way of solving crime. It is an entire way of thinking, a mindset that can be applied to countless enterprises far removed from the foggy streets of the London underworld. It is an approach born out of the scientific method that transcends science and crime both and can serve as a model for thinking, a way of being, even, just as powerful in our time as it was in Conan Doyle’s. And that, I would argue, is the secret to Holmes’s enduring, overwhelming, and ubiquitous appeal.
When Conan Doyle created Sherlock Holmes, he didn’t think much of his hero. It’s doubtful that he set out intentionally to create a model for thought, for decision making, for how to structure, lay out, and solve problems in our minds. And yet that is precisely what he did. He created, in effect, the perfect spokesperson for the revolution in science and thought that had been unfolding in the preceding decades and would continue into the dawn of the new century. In 1887, Holmes became a new kind of detective, an unprecedented thinker who deployed his mind in unprecedented ways. Today, Holmes serves an ideal model for how we can think better than we do as a matter of course.
In many ways, Sherlock Holmes was a visionary. His explanations, his methodology, his entire approach to thought presaged developments in psychology and neuroscience that occurred over a hundred years after his birth—and over eighty years after his creator’s death. But somehow, too, his way of thought seems almost inevitable, a clear product of its time and place in history. If the scientific method was coming into its prime in all manner of thinkings and doings—from evolution to radiography, general relativity to the discovery of germs and anesthesia, behaviorism to psychoanalysis—then why ever not in the principles of thought itself?
In Arthur Conan Doyle’s own estimation, Sherlock Holmes was meant from the onset to be an embodiment of the scientific, an ideal that we could aspire to, if never emulate altogether (after all, what are ideals for if not to be just a little bit out of reach?). Holmes’s very name speaks at once of an intent beyond a simple detective of the old-fashioned sort: it is very likely that Conan Doyle chose it as a deliberate tribute to one of his childhood idols, the philosopher-doctor Oliver Wendell Holmes, Sr., a figure known as much for his writing as for his contributions to medical practice. The detective’s character, in turn, was modeled after another mentor, Dr. Joseph Bell, a surgeon known for his powers of close observation. It was said that Dr. Bell could tell from a single glance that a patient was a recently discharged noncommissioned officer in a Highland regiment, who had just returned from service in Barbados, and that he tested routinely his students’ own powers of perception with methods that included self-experimentation with various noxious substances. To students of Holmes, that may all sound rather familiar. As Conan Doyle wrote to Bell, “Round the centre of deduction and inference and observation which I have heard you inculcate, I have tried to build up a man who pushed the thing as far as it would go—further occasionally. . . .” It is here, in observation and inference and deduction, that we come to the heart of what it is exactly that makes Holmes who he is, distinct from every other detective who appeared before, or indeed, after: the detective who elevated the art of detection to a precise science.
We first learn of the quintessential Sherlock Holmes approach in A Study in Scarlet, the detective’s first appearance in the public eye. To Holmes, we soon discover, each case is not just a case as it would appear to the officials of Scotland Yard—a crime, some facts, some persons of interest, all coming together to bring a criminal to justice—but is something both more and less. More, in that it takes on a larger, more general significance, as an object of broad speculation and inquiry, a scientific conundrum, if you will. It has contours that inevitably were seen before in earlier problems and will certainly repeat again, broader principles that can apply to other moments that may not even seem at first glance related. Less, in that it is stripped of any accompanying emotion and conjecture—all elements that are deemed extraneous to clarity of thought—and made as objective as a nonscientific reality could ever be. The result: the crime as an object of strict scientific inquiry, to be approached by the principles of the scientific method. Its servant: the human mind.
What Is the Scientific Method of Thought?
When we think of the scientific method, we tend to think of an experimenter in his laboratory, probably holding a test tube and wearing a white coat, who follows a series of steps that runs something like this: make some observations about a phenomenon; create a hypothesis to explain those observations; design an experiment to test the hypothesis; run the experiment; see if the results match your expectations; rework your hypothesis if you must; lather, rinse, and repeat. Simple seeming enough. But how to go beyond that? Can we train our minds to work like that automatically, all the time?
Holmes recommends we start with the basics. As he says in our first meeting with him, “Before turning to those moral and mental aspects of the matter which present the greatest difficulties, let the enquirer begin by mastering more elementary problems.” The scientific method begins with the most mundane seeming of things: observation. Before you even begin to ask the questions that will define the investigation of a crime, a scientific experiment, or a decision as apparently simple as whether or not to invite a certain friend to dinner, you must first explore the essential groundwork. It’s not for nothing that Holmes calls the foundations of his inquiry “elementary.” For, that is precisely what they are, the very basis of how something works and what makes it what it is.
And that is something that not even every scientist acknowledges outright, so ingrained is it in his way of thinking. When a physicist dreams up a new experiment or a biologist decides to test the properties of a newly isolated compound, he doesn’t always realize that his specific question, his approach, his hypothesis, his very view of what he is doing would be impossible without the elemental knowledge at his disposal, that he has built up over the years. Indeed, he may have a hard time telling you from where exactly he got the idea for a study—and why he first thought it would make sense.
After World War II, physicist Richard Feynman was asked to serve on the State Curriculum Commission, to choose high school science textbooks for California. To his consternation, the texts appeared to leave students more confused than enlightened. Each book he examined was worse than the one prior. Finally, he came upon a promising beginning: a series of pictures, of a windup toy, an automobile, and a boy on a bicycle. Under each was a question: “What makes it go?” At last, he thought, something that was going to explain the basic science, starting with the fundamentals of mechanics (the toy), chemistry (the car), and biology (the boy). Alas, his elation was short lived. Where he thought to finally see explanation, real understanding, he found instead four words: “Energy makes it go.” But what was that? Why did it make it go? How did it make it go? These questions weren’t ever acknowledged, never mind answered. As Feynman put it, “That doesn’t mean anything. . . . It’s just a word!” Instead, he argued, “What they should have done is to look at the windup toy, see that there are springs inside, learn about springs, learn about wheels, and never mind ‘energy.’ Later on, when the children know something about how the toy actually works, they can discuss the more general principles of energy.”
Feynman is one of the few who rarely took his knowledge base for granted, who always remembered the building blocks, the elements that lay underneath each question and each principle. And that is precisely what Holmes means when he tells us that we must begin with the basics, with such mundane problems that they might seem beneath our notice. How can you hypothesize, how can you make testable theories if you don’t first know what and how to observe, if you don’t first understand the fundamental nature of the problem at hand, down to its most basic elements? (The simplicity is deceptive, as you will learn in the next two chapters.)
The scientific method begins with a broad base of knowledge, an understanding of the facts and contours of the problem you are trying to tackle. In the case of Holmes in A Study in Scarlet, it’s the mystery behind a murder in an abandoned house on Lauriston Gardens. In your case, it may be a decision whether or not to change careers. Whatever the specific issue, you must define and formulate it in your mind as specifically as possible—and then you must fill it in with past experience and present observation. (As Holmes admonishes Lestrade and Gregson when the two detectives fail to note a similarity between the murder being investigated and an earlier case, “There is nothing new under the sun. It has all been done before.”)
Only then can you move to the hypothesis-generation point. This is the moment where the detective engages his imagination, generating possible lines of inquiry into the course of events, and not just sticking to the most obvious possibility—in A Study in Scarlet, for instance, rache need not be Rachel cut short, but could also signify the German for revenge—or where you might brainstorm possible scenarios that may arise from pursuing a new job direction. But you don’t just start hypothesizing at random: all the potential scenarios and explanations come from that initial base of knowledge and observation.
Only then do you test. What does your hypothesis imply? At this point, Holmes will investigate all lines of inquiry, eliminating them one by one until the one that remains, however improbable, must be the truth. And you will run through career change scenarios and try to play out the implications to their logical, full conclusion. That, too, is manageable, as you will later learn.
But even then, you’re not done. Times change. Circumstances change. That original knowledge base must always be updated. As our environment changes, we must never forget to revise and retest out hypotheses. The revolutionary can, if we’re not careful, become the irrelevant. The thoughtful can become unthinking through our failure to keep engaging, challenging, pushing.
That, in a nutshell, is the scientific method: understand and frame the problem; observe; hypothesize (or imagine); test and deduce; and repeat. To follow Sherlock Holmes is to learn to apply that same approach not just to external clues, but to your every thought—and then turn it around and apply it to the every thought of every other person who may be involved, step by painstaking step.
When Holmes first lays out the theoretical principles behind his approach, he boils it down to one main idea: “How much an observant man might learn by an accurate and systematic examination of all that came his way.” And that “all” includes each and every thought; in Holmes’s world, there is no such thing as a thought that is taken at face value. As he notes, “From a drop of water, a logician could infer the possibility of an Atlantic or a Niagara without having seen or heard of one or the other.” In other words, given our existing knowledge base, we can use observation to deduce meaning from an otherwise meaningless fact. For what kind of scientist is that who lacks the ability to imagine and hypothesize the new, the unknown, the as-of-yet untestable?
This is the scientific method at its most basic. Holmes goes a step further. He applies the same principle to human beings: a Holmesian disciple will, “on meeting a fellow-mortal, learn at a glance to distinguish the history of the man and the trade or profession to which he belongs. Puerile as such an exercise may seem, it sharpens the faculties of observation, and teaches one where to look and what to look for.” Each observation, each exercise, each simple inference drawn from a simple fact will strengthen your ability to engage in ever-more-complex machinations. It will lay the groundwork for new habits of thinking that will make such observation second nature.
That is precisely what Holmes has taught himself—and can now teach us—to do. For, at its most basic, isn’t that the detective’s appeal? Not only can he solve the hardest of crimes, but he does so with an approach that seems, well, elementary when you get right down to it. This approach is based in science, in specific steps, in habits of thought that can be learned, cultivated, and applied.
That all sounds good in theory. But how do you even begin? It does seem like an awfully big hassle to always think scientifically, to always have to pay attention and break things down and observe and hypothesize and deduce and everything in between. Well, it both is and isn’t. On the one hand, most of us have a long way to go. As we’ll see, our minds aren’t meant to think like Holmes by default. But on the other hand, new thought habits can be learned and applied. Our brains are remarkably adept at learning new ways of thinking—and our neural connections are remarkably flexible, even into old age. By following Holmes’s thinking in the following pages, we will learn how to apply his methodology to our everyday lives, to be present and mindful and to treat each choice, each problem, each situation with the care it deserves. At first it will seem unnatural. But with time and practice it will come to be as second nature for us as it is for him.
Pitfalls of the Untrained Brain
One of the things that characterizes Holmes’s thinking—and the scientific ideal—is a natural skepticism and inquisitiveness toward the world. Nothing is taken at face value. Everything is scrutinized and considered, and only then accepted (or not, as the case may be). Unfortunately, our minds are, in their default state, averse to such an approach. In order to think like Sherlock Holmes, we first need to overcome a sort of natural resistance that pervades the way we see the world.
Most psychologists now agree that our minds operate on a so-called two-system basis. One system is fast, intuitive, reactionary—a kind of constant fight-or-flight vigilance of the mind. It doesn’t require much conscious thought or effort and functions as a sort of status quo auto pilot. The other is slower, more deliberative, more thorough, more logical—but also much more cognitively costly. It likes to sit things out as long as it can and doesn’t step in unless it thinks it absolutely necessary.
Because of the mental cost of that cool, reflective system, we spend most of our thinking time in the hot, reflexive system, basically ensuring that our natural observer state takes on the color of that system: automatic, intuitive (and not always rightly so), reactionary, quick to judge. As a matter of course, we go. Only when something really catches our attention or forc
es us to stop or otherwise jolts us do we begin to know, turning on the more thoughtful, reflective, cool sibling.
I’m going to give the systems monikers of my own: the Watson system and the Holmes system. You can guess which is which. Think of the Watson system as our naive selves, operating by the lazy thought habits—the ones that come most naturally, the so-called path of least resistance—that we’ve spent our whole lives acquiring. And think of the Holmes system as our aspirational selves, the selves that we’ll be once we’re done learning how to apply his method of thinking to our everyday lives—and in so doing break the habits of our Watson system once and for all.
When we think as a matter of course, our minds are preset to accept whatever it is that comes to them. First we believe, and only then do we question. Put differently, it’s like our brains initially see the world as a true/false exam where the default answer is always true. And while it takes no effort whatsoever to remain in true mode, a switch of answer to false requires vigilance, time, and energy.
Psychologist Daniel Gilbert describes it this way: our brains must believe something in order to process it, if only for a split second. Imagine I tell you to think of pink elephants. You obviously know that pink elephants don’t actually exist. But when you read the phrase, you just for a moment had to picture a pink elephant in your head. In order to realize that it couldn’t exist, you had to believe for a second that it did exist. We understand and believe in the same instant. Benedict de Spinoza was the first to conceive of this necessity of acceptance for comprehension, and, writing a hundred years before Gilbert, William James explained the principle as “All propositions, whether attributive or existential, are believed through the very fact of being conceived.” Only after the conception do we effortfully engage in disbelieving something—and, as Gilbert points out, that part of the process can be far from automatic.