The Mysterious Affair at Styles centers around the murder of Emily Inglethorp, but the novel is really about the Belgian detective Hercule Poirot and his incredible powers of deduction. The murder takes place quite early in the novel, and Poirot spends the rest of the book piecing together what happened. His willingness to pay close attention to each and every aspect of the case ultimately suggests that successful detective work requires fastidious organization, extreme patience, and a keen eye for details that seem out of place. To highlight the importance of this kind of levelheaded reasoning, the novel juxtaposes Poirot’s highly methodical mind with Hastings’s bumbling and impulsive nature. Whereas Hastings (the narrator) often gets excited and jumps to conclusions, Poirot takes time to work out every detail, always confirming that things make sense before acting on his assumptions. In particular, he pays close attention to things that don’t add up, never letting himself discard a piece of information simply because it doesn’t make sense. In fact, he regards details that don’t make sense as especially important, approaching any lapse of reason or logic as a potential clue.
At the initial court hearing, for instance, Alfred Inglethorp doesn’t try very hard to prove his own innocence—it even seems like he says all the wrong things on purpose. Whereas Hastings doesn’t make much of this, Poirot notices Alfred’s strange behavior and realizes he’s behaving irrationally. At first, Alfred’s reasons for not trying to clear his name are unclear to Poirot, but it’s exactly this lack of clarity that eventually helps the detective crack the case: Alfred wanted to be arrested because he knew the evidence was—at that point—too thin to actually convict him, and a person can’t be tried twice for the same crime in England. What initially seemed like irrational behavior was therefore actually very logical and deliberate. Poirot uses a similar kind of deductive reasoning when he hypothesizes that Emily Inglethorp must have burned her will before dying. After all, she wouldn’t have wanted a fire in her bedroom on a hot summer night unless she intended to burn something. Everyone overlooks this detail, but Poirot seizes on the fire because it doesn’t fit in with the rest of the story. Instead of focusing exclusively on evidence that makes sense, then, the novel suggests that paying attention to out-of-place or illogical details is often the key to good detective work.
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Logic and Deduction Quotes in The Mysterious Affair at Styles
His watchful and attentive manner never varied. From the very first I took a firm and rooted dislike to him, and I flatter myself that my first judgements are usually fairly shrewd.
“Like a good detective story myself,” remarked Miss Howard. “Lots of nonsense written, though. Criminal discovered in last chapter. Everyone dumbfounded. Real crime—you’d know at once.”
“There have been a great number of undiscovered crimes,” I argued.
“Don’t mean the police, but the people that are right in it. The family. You couldn’t really hoodwink them. They’d know.”
We went slowly down the stairs. I was violently excited. I have a certain talent for deduction, and Dr. Bauerstein’s manner had started a flock of wild surmises in my mind.
“The mind is confused? Is it not so? Take time, mon ami. You are agitated; you are excited—it is but natural. Presently, when we are calmer, we will arrange the facts, neatly, each in his proper place. We will examine—and reject. Those of importance we will put on one side; those of no importance, pouf!”—he screwed up his cherublike face, and puffed comically enough—“blow them away!”
“[…] One fact leads to another—so we continue. Does the next fit in with that? A merveille! Good! We can proceed. This next little fact—no! Ah, that is curious! There is something missing—a link in the chain that is not there. We examine. We search. And that little curious fact, that possibly paltry little detail that will not tally, we put it here!” He made an extravagant gesture with his hand. “It is significant! It is tremendous!”
“Beware! Peril to the detective who says: ‘It is so small—it does not matter. It will not agree. I will forget it.’ That way lies confusion! Everything matters.”
“[…] Well, strychnine is a fairly rapid poison. Its effects would be felt very soon, probably in about an hour. Yet, in Mrs. Inglethorp’s case, the symptoms do not manifest themselves until five o’clock the next morning: nine hours! But a heavy meal, taken at about the same time as the poison, might retard its effects, though hardly to that extent. Still, it is a possibility to be taken into account. But, according to you, she ate very little for supper, and yet the symptoms do not develop until early the next morning! Now that is a curious circumstance, my friend. Something may arise at the autopsy to explain it. In the meantime, remember it.”
I had the utmost difficulty in controlling my excitement. Unknown to herself, Annie had provided us with an important piece of evidence. How she would have gaped if she had realized that her “coarse kitchen salt” was strychnine, one of the most deadly poisons known to mankind. I marvelled at Poirot’s calm. His self-control was astonishing. I awaited his next question with impatience, but it disappointed me.
“You gave too much rein to your imagination. Imagination is a good servant, and a bad master. The simplest explanation is always the most likely.”
“I had forgotten that,” I said thoughtfully. “That is as enigmatical as ever. It seems incredible that a woman like Mrs. Cavendish, proud and reticent to the last degree should interfere so violently in what was certainly not her affair.”
“Precisely. […]”
“It is certainly curious,” I agreed. “Still, it is unimportant, and need not be taken into account.”
A groan burst from Poirot.
“What have I always told you? Everything must be taken into account. If the fact will not fit the theory—let the theory go.”
“Yes, yes, too conclusive,” continued Poirot, almost to himself. “Real evidence is usually vague and unsatisfactory. It has to be examined—sifted. But here the whole thing is cut and dried. No, my friend, this evidence has been very cleverly manufactured—so cleverly that it has defeated its own ends.”
“Who put it in the chest, I wonder?”
“Someone with a good deal of intelligence,” remarked Poirot drily. “You realize that he chose the one place in the house to hide it where its presence would not be remarked? Yes, he is intelligent. But we must be more intelligent. We must be so intelligent that he does not suspect us of being intelligent at all.”
“Because she cares for someone else, mon ami.”
“Oh!” What did he mean? In spite of myself, an agreeable warmth spread over me. I am not a vain man where women are concerned, but I remembered certain evidences, too lightly thought of at the time, perhaps, but which certainly seemed to indicate—
“I say, that’s playing it a bit low down,” I protested.
“Not all. We have to deal with a most clever and unscrupulous man, and we must use any means in our power—otherwise he will slip through our fingers. That is why I have been careful to remain in the background. All the discoveries have been made by Japp, and Japp will take all the credit. […]”
“Impossible!” I exclaimed. “She had only made it out that very afternoon!”
“Nevertheless, mon ami, it was Mrs. Inglethorp. Because, in no other way can you account for the fact that, on one of the hottest days of the year, Mrs. Inglethorp ordered a fire to be lighted in her room.”
“Because, mon ami, it is the law of your country that a man once acquitted can never be tried again for the same offence. Aha! But it was clever—his idea! Assuredly, he is a man of method. See here, he knew that in his position he was bound to be suspected, so he conceived the exceedingly clever idea of preparing a lot of manufactured evidence against himself. He wished to be suspected. He wished to be arrested. He would then produce his irreproachable alibi—and, hey presto, he was safe for life!”
