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Lessons from Sherlock Holmes: Don’t Try to Make Bricks without Clay

If this week’s lesson sounds a bit repetitive, it is meant to, not only because it touches on so many of the poor thought habits that Holmes singles out in his attempts to craft Watson into an abler logician, but also because it is the last–for now, at least–of the "Lessons from Sherlock Holmes" series, [...]

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


If this week’s lesson sounds a bit repetitive, it is meant to, not only because it touches on so many of the poor thought habits that Holmes singles out in his attempts to craft Watson into an abler logician, but also because it is the last–for now, at least–of the “Lessons from Sherlock Holmes” series, and as such, is aimed at capturing one of our most common (and most commonly ignored) errors of thought: that of skipping over the details and jumping straight into the conclusions.

Not to worry. Holmes is not gone for good. He will be making the occasional appearance in a new series that I will be starting next week; but more on that later. For now, let’s turn one more time to the master detective to see what light his latest exclamation can shed on the inner workings of our minds.

In “The Adventure of the Copper Beeches,” a young woman consults Holmes on the advisability of taking a strange–albeit remarkably well-paying–position as a governess in the country. Though Holmes tells her that, “it is not the situation which I should like to see a sister of mine apply for,” she proceeds to take the job. Holmes then predicts that he and Watson will hear from her shortly–trouble is certainly ahead, else why would this young woman be given a high salary for such light duties, along with being asked to comply with such extraordinary demands as changing the length of her hair and wearing a particular color of dress? But in the meantime, he can’t seem to get the case out of his mind. As Watson notes,


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I observed that he sat frequently for half and hour on end, with knitted brows and an abstracted air, but he swept the matter away with a wave of his hand when I mentioned it. “Data! Data! Data!” he cried impatiently. “I can’t make bricks without clay.” And yet he would always wind up by muttering again that no sister of his should ever have accepted such a situation.

Holmes’s exclamation is perhaps one of the most famous lines he has ever spoken, and with good reason. For, it points to a tendency that we all too often indulge and that is all too easy to indulge in: the tendency to do the impossible, to make bricks without their proper material. To create something, in this case, a theory, in the absence of anything on which to base it. To speculate absent any hard facts.

The ease of speculation…

Just think how easy it is to do. I say “governess,” and doubtless, images of governesses, acquired from reading, movies, and wherever else, rise up in your head. Maybe you see Miss Hunter as Jane Eyre and right away, start to imagine something sinister hiding in the shadows. Or maybe you see her like Mary Poppins and start smiling at the adventures that may lie in store–certainly a far less dark picture than the first. Or maybe you see her as something else entirely; but whatever you do, you see her in some fashion, a fashion that is in large part determined by your own experiences and associations.

It is easy to forget that these are no more than general images that have no concrete facts to back them up. We know next to nothing of the situation into which Violet Hunter is entering. It may be like Jane Eyre’s or Mary Poppins’s, or it may be entirely different. In any case, we have no basis for conclusions prior to learning more.

But how easy it is to speculate even without any further information. How many intricate scenarios can be drawn from a few strange facts. Miss Hunter herself engages in just such scenario-generating, positing that while her employer himself is a kind and good-natured man, his wife is a lunatic–perhaps Violet really has read too much Charlotte Bront?–and so he indulges her every whim to prevent an outbreak. But Holmes, after telling Violet Hunter that she might be in danger, says only, “it would cease to be a danger if we could define it.” He recognizes that the three facts that they do have are not nearly enough to go on and so refuses to speculate further. He may suspect that something doesn’t fit, but he will wait for more clay before he starts making the bricks of conclusions.

…And the necessity of resisting it

When Holmes calls for data, for his “clay,” he is, in essence, warning Watson of the dangers of jumping to conclusions when what we should be doing is gathering some facts to base those conclusions on. Of course, there is room for some speculation–clearly, Holmes knows something is off and knits his brows at the problem–but any theory that may arise must, as the detective has said repeatedly, cover all of the known facts. And what are the facts here, exactly? Only what we know from the girl before she has ever set foot on the property. She has not seen the wife. She has not seen her employer outside of a few minutes in the employment office. She has no notion whatsoever of the particulars of her new situation, save that it is in the country and will require some changes in her appearance. There are too many possible theories to cover what we do know to be of any use–the lunatic wife is but one of any number of possibilities–and not a single actual fact from the situation itself. Theories help explain facts; they do not and cannot replace them.

When we encounter something that captures our attention–in this particular case, it’s the incongruity of job compensation and demands and the presence of strange stipulations, such as length of hair and color of dress–it stands to reason that we would take note. Something does not add up. Why not give it some thought? But when we take note, we tend to go a step further, jumping ahead of ourselves and creating possible explanations and scenarios that might fit. Even Holmes seems to indulge in something of the sort, when Watson notices his concentrated thinking–though he refuses to take his speculations beyond his own mind and into the world at large by sharing them with Watson and thus giving them more definitive shape.

But most of us aren’t as disciplined. We latch on, and we run with it. Instead of stopping to reflect, we push to conclude. Holmes has warned us many times, in different guises, not to get ahead of ourselves in reasoning before we have sufficient data. Why the need for such repeated, empathic reminders? Because jumping to conclusions is all too easy. What is difficult is not jumping to them.

We jump to conclusions for any number of reasons. We may think we have the data when we don’t and thus end up forming an impression before we’ve even seen the necessary elements on which to base it. We may read more into the little that is known than we should, using our version of the facts and not the facts themselves. We may fail to take the necessary step back to see beyond mere detail, which may end up being meaningless on its own. And in each case, we take mental shortcuts, falling back on the same heuristics and biases that I’ve explored previously in this series. We think in terms of what we know and what we’ve experienced. We simplify and judge when we should be simply observing. Does Violet Hunter really know her employer is kind? She has never interacted with him beyond their initial encounter and has simply equated a large some of money with kindness. The two may coincide, but they certainly don’t have to. Does she know his wife is eccentric? Here, she has even less to go on–not a single fact, as it turns out. And yet that doesn’t stop her from drawing her own inferences.

Such speculation abounds in all walks of life–in politics, in science, in everyday decisions and experiences. It’s easy to jump to conclusions from a few glaring elements or words (an electric blue dress, a preposterous salary) without stopping to gather the full story–or even realizing that what we have is but a fraction, and a not very meaningful fraction on its own, at that, of the whole. It’s easy to just glimpse a piece of the puzzle and conclude that we know what the whole thing resembles. And it’s hard to remember that the same piece can fit in any number of ways into any number of puzzles; until we find those corner pieces and start to fill in the center, we cannot possibly think we’ve found the single possible image that will emerge once the jigsaw is complete.

We can’t actually make bricks without clay. But that doesn’t mean we don’t try, substituting just about anything else for the pleasure of building itself, material be damned. After all, it is much more fun to build and to create than it is to gather up the raw materials–it provides much more of a sense of accomplishment. But if we just stop for a second to consider the fact that it would be far easier–and more reliable–to just wait to build until the proper clay can be found, we may find ourselves spared many a grievous intellectual (or other) error and living in a far stronger house, one that is build of actual bricks, not makeshift brick substitutes that will likely collapse under any real pressure.

Photo credit: Holmes and Watson meet with Violet Hunter, in “The Adventure of the Copper Beeches.” By Sidney Paget (1860 – 1908) (Strand Magazine) [Public domain], via Wikimedia Commons

Previously in this series:

Don’t Just See, Observe: What Sherlock Holmes Can Teach Us About Mindful Decisions Lessons from Sherlock Holmes: Paying Attention to What Isn’t There Lessons from Sherlock Holmes: Cultivate What You Know to Optimize How You Decide Lessons from Sherlock Holmes: Perspective Is Everything, Details Alone Are Nothing Lessons from Sherlock Holmes: Don’t Underestimate the Importance of Imagination Lessons from Sherlock Holmes: Confidence Is good; Overconfidence, Not So Much Lessons from Sherlock Holmes: The Situation Is in the Mindset of the Observer Lessons from Sherlock Holmes: The Power of Public Opinion Lessons from Sherlock Holmes: Don’t Tangle Two Lines of Thought Lessons from Sherlock Holmes: Breadth of Knowledge Is Essential Lessons from Sherlock Holmes: Don’t Decide Before You Decide Lessons from Sherlock Holmes: Trust in The Facts, Not Your Version of Them Lessons from Sherlock Holmes: Don’t Judge a Man by His Face Lessons from Sherlock Holmes: The Importance of Perspective-Taking Lessons from Sherlock Holmes: From Perspective-Taking to Empathy Lessons from Sherlock Holmes: Why Most of Us Wouldn’t Be Able to Tell That Watson Fought in Afghanistan Lessons from Sherlock Holmes: Preconceptions and the Blunting of Imagination

Maria Konnikova is a science journalist and professional poker player. She is author of the best-selling books The Biggest Bluff (Penguin Press, 2020), The Confidence Game (Viking Press, 2016) and Mastermind: How to Think Like Sherlock Holmes (Viking Press, 2013).

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