Mastermind: How to Think Like Sherlock Holmes (27 page)

We need, in essence, to do just what the CRT teaches us: reflect, inhibit, and edit. Plug System Holmes in, check the tendency to gather detail thoughtlessly, and instead focus—thoughtfully—on the details we already have. All of those observations? We need to learn to divide them in our minds in order to maximize productive reasoning. We have to learn when
not
to think of them as well as when to bring them in. We have to learn to concentrate—reflect, inhibit, edit—otherwise we may end up getting exactly nowhere on any of the myriad ideas floating
through our heads. Mindfulness and motivation are essential to successful deduction.

But essential never means simple, nor does it mean sufficient. Even with Silver Blaze, Holmes, as focused and motivated as he is, finds it difficult to sift through all of the possible lines of thought. As he tells Watson once Silver Blaze is recovered, “I confess that any theories which I had formed from the newspaper reports were entirely erroneous. And yet there were indications there, had they not been overlaid by other details which concealed their true import.” The separation of crucial and incidental, the backbone of any deduction, can be hard for even the best-trained minds. That’s why Holmes doesn’t run off based on his initial theories. He first does precisely what he urges us to do: lay the facts out in a neat row and proceed from there. Even in his mistakes, he is deliberative and Holmes-like, not letting System Watson act though it may well want to.

How does he do this? He goes at his own pace, ignoring everyone who urges haste. He doesn’t let anyone affect him. He does what he needs to do. And beyond that he uses another simple trick. He tells Watson everything—something that occurs with great regularity throughout the Holmes canon (and you thought it was just a clever expository device!). As he tells the doctor before he delves into the pertinent observations, “nothing clears up a case so much as stating it to another person.” It’s the exact same principle we’ve seen in operation before: stating something through, out loud, forces pauses and reflection. It mandates mindfulness. It forces you to consider each premise on its logical merits and allows you to slow down your thinking so that you do not blunder into a feminist Linda. It ensures that you do not let something that is of real significance go by simply because it didn’t catch your attention enough or fit with the causal story that you have (subconsciously, no doubt) already created in your head. It allows your inner Holmes to listen and forces your Watson to pause. It allows you to confirm that you’ve actually understood, not just thought you understood because it seemed right.

Indeed, it is precisely in stating the facts to Watson that Holmes realizes the thing that will allow him to solve the case. “It was while I was in the carriage, just as we reached the trainer’s house, that the immense significance
of the curried mutton occurred to me.” The choice of a dinner is easy to mistake for triviality, until you state it along with everything else and realize that the dish was perfectly engineered to hide the smell and taste of powdered opium, the poison that was used on the stable boy. Someone who didn’t know the curried mutton was to be served would never risk using a poison that could be tasted. The culprit, then, is someone who knew what was for dinner. And that realization prompts Holmes to his famous conclusion: “Before deciding that question I had grasped the significance of the silence of the dog, for one true inference invariably suggests others.” Start on the right track, and you are far more likely to remain there.

While you’re at it, make sure you are recalling
all
of your observations, all of the possible permutations that you’ve thought up in your imaginative space, and avoiding those instances that are not part of the picture. You can’t just focus on the details that come to mind most easily or the ones that seem to be representative or the ones that seem to be most salient or the ones that make the most intuitive sense. You have to dig deeper. You would likely never judge Linda a likely bank teller from her description, though you very well might judge her a likely feminist. Don’t let that latter judgment color what follows; instead, proceed with the same logic that you did before, evaluating each element separately and objectively as part of a consistent whole. A likely bank teller? Absolutely not. And so, a feminist one? Even less probable.

You have to remember, like Holmes, all of the details about Silver Blaze’s disappearance, stripped of all of the papers’ conjectures and the theories your mind may have inadvertently formed as a result. Never would Holmes call Linda a feminist bank teller, unless he was first certain that she was a bank teller.

The Improbable Is Not Impossible

In
The Sign of Four
, a robbery and murder are committed in a small room, locked from the inside, on the top floor of a rather large estate. How in the world did the criminal get inside to do the deed? Holmes enumerates the possibilities: “The door has not been opened since last
night,” he tells Watson. “Window is snibbed on the inner side. Framework is solid. No hinges at the side. Let us open it. No water-pipe near. Roof quite out of reach.”

Then how to possibly get inside? Watson ventures a guess: “The door is locked, the window is inaccessible. Was it through the chimney?”

No, Holmes tells him. “The grate is much too small. I had already considered that possibility.”

“How then?” asks an exasperated Watson.

“You will not apply my precept.” Holmes shakes his head. “How often have I said to you that when you have eliminated the impossible, whatever remains,
however improbable
, must be the truth? We know that he did not come through the door, the window, or the chimney. We also know that he could not have been concealed in the room, as there is no concealment possible. Whence, then, did he come?”

And then, at last, Watson sees the answer: “He came from the hole in the roof.” And Holmes’s reply, “Of course he did. He must have done so,” makes it seem the most logical entrance possible.

It isn’t, of course. It is highly improbable, a proposition that most people would never consider, just as Watson, trained as he is in Holmes’s approach, failed to do without prompting. Just like we find it difficult to separate the incidental from the truly crucial, so, too, we often fail to consider the improbable—because our minds dismiss it as impossible before we even give it its due. And it’s up to System Holmes to shock us out of that easy narrative and force us to consider that something as unlikely as a rooftop entrance may be the very thing we need to solve our case.

Lucretius called a fool someone who believes that the tallest mountain that exists in the world and the tallest mountain he has ever observed are one and the same. We’d probably brand someone who thought that way foolish as well. And yet we do the same thing every single day. Author and mathematician Nassim Taleb even has a name for it, inspired by the Latin poet: the Lucretius underestimation. (And back in Lucretius’s day, was it so strange to think that your world was limited to what you knew? In some ways, it’s smarter than the mistakes we make today given the ease of knowledge at our disposal.)

Simply put, we let our own personal past experience guide what we
perceive to be possible. Our repertoire becomes an anchor of sorts; it is our reasoning starting point, our place of departure for any further thoughts. And even if we try to adjust from our egocentric perspective, we tend not to adjust nearly enough to matter, remaining stubbornly skewed in a self-directed approach. It’s our storytelling proclivity in another guise: we imagine stories based on the ones we’ve experienced, not the ones we haven’t.

Learning of historical precedent as well matters little, since we don’t learn in the same way from description as we do from experience. It’s something known as the description-experience gap. Perhaps Watson had read at one time or another about a daring rooftop entrance, but because he has never had direct experience from it, he will not have processed the information in the same way and is not likely to use it in the same manner when trying to solve a problem. Lucretius’s fool? Having read of high peaks, he may
still
not believe they exist.
I want to see them with my own two eyes,
he’ll say.
What am I, some kind of fool?
Absent a direct precedent, the improbable seems so near impossible that Holmes’s maxim falls by the wayside.

And yet distinguishing the two is an essential ability to have. For, even if we have successfully separated the crucial from the incidental, even if we’ve gathered all of the facts (and their implications) and have focused on the ones that are truly relevant, we are lost if we don’t let our minds think of the roof, however unlikely it is, as a possible entry point into a room. If, like Watson, we dismiss it out of hand—or fail to even think about—we will never be able to deduce those alternatives that would flow directly from our reasoning if only we’d let them.

We use the best metric of the future—the past. It’s natural to do so, but that doesn’t mean it’s accurate. The past doesn’t often make room for the improbable. It constrains our deduction to the known, the likely, the probable. And who is to say that the evidence, if taken together and properly considered, doesn’t lead to an alternative beyond these realms?

Let’s go back for a moment to “Silver Blaze.” Sherlock Holmes emerges triumphant, it’s true—the horse is found, as is the trainer’s murderer—but not after a delay that is uncharacteristic of the great detective. He is late to the investigation (three days late, to be specific), losing valuable
time at the scene. Why? He does just what he reprimands Watson for doing: he fails to apply the precept that the improbable is not yet the impossible, that it must be considered along with the more likely alternatives.

As Holmes and Watson head to Dartmoor to help with the investigation, Holmes mentions that on Tuesday evening both the horse’s owner and Inspector Gregson had telegraphed for his assistance on the case. The flummoxed Watson responds, “Tuesday evening! And this is Thursday morning. Why didn’t you go down yesterday?” To which Holmes answers, “Because I made a blunder, my dear Watson—which is, I am afraid, a more common occurrence than anyone would think who only knew me through your memoirs. The fact is that I could not believe it possible that the most remarkable horse in England could long remain concealed, especially in so sparsely inhabited a place as the north of Dartmoor.”

Holmes has dismissed the merely improbable as impossible and has failed to act in a timely fashion as a result. In so doing, he has reversed the usual Holmes-Watson exchange, making Watson’s reprimand uncharacteristically well warranted and on point.

Even the best and sharpest mind is necessarily subject to its owner’s unique experience and world perception. While a mind such as Holmes’s is, as a rule, able to consider even the most remote of possibilities, there are times when it, too, becomes limited by preconceived notions, by what is available to its repertoire at any given point. In short, even Holmes is limited by the architecture of his brain attic.

Holmes sees a horse of exceptional appearance missing in a rural area. Everything in his experience tells him it can’t go missing for long. His logic is as follows: if the horse is the most remarkable such animal in the whole of England, then how could it go under the radar in a remote area where hiding places are limited? Surely someone would notice the beast, dead or alive, and make a report. And that would be perfect deduction from the facts,
if
it happened to be true. But it is Thursday, the horse has been missing since Tuesday, and the report has failed to come. What is it then that Holmes failed to take into account?

A horse couldn’t remain concealed
if it could still be recognized as that horse.
The possibility of disguising the animal doesn’t cross the great detective’s
mind; if it had, surely he wouldn’t have discounted the likelihood of the animal remaining hidden. What Holmes sees isn’t just what there is; he is also seeing what he knows. Were we to witness something that in no way fit with past schemas, had no counterpart in our memory, we would likely not know how to interpret it—or we may even fail to see it altogether, and instead see what we were expecting all along.

Think of it as a complex version of any one of the famous Gestalt demonstrations of visual perception, whereby we are easily able to see one thing in multiple ways, depending on the context of presentation.

For instance, consider this picture:

Do you see the middle figure as a
B
or a 13? The stimulus remains the same, but what we see is all a matter of expectation and context. A disguised animal? Not in Holmes’s repertoire, however vast it might be, and so he does not even consider the possibility. Availability—from experience, from contextual frames, from ready anchors—affects deduction. We wouldn’t deduce a
B
if we took away the
A
and
C
, just like we’d never deduce a 13 were the 12 and 14 to be removed. It wouldn’t even cross our minds, even though it is highly possible, merely improbable given the context. But if the context were to shift slightly? Or if the missing row were to be present, only hidden from our view? That would change the picture, but it wouldn’t necessarily change the choices we consider.