How does a certain phrase make Montresor an unreliable narrator in The Cask of Amontillado?

First, many critics presume that Montresor is speaking a deathbed confession to a priest. This would account for his finally revealing the murder which he had kept successfully concealed. Assuming he is dying when he speaks would mean that he would face no consequences for the murder, and besides the priest could not break the seal of confession to reveal it. Thus the reference to knowledge of the "soul" would refer to a confessor's knowledge of the soul of the penitent.

For unreliability, the statement "will not suppose . . . I gave utterance" casts Montresor as someone who conceals the truth. His self-interest and his self-discipline in dissimulating is apparent in the way he pretends to everyone that he bears no malice towards Fortunato. This establishes him as untrustworthy.

How does a certain phrase make Montresor an unreliable narrator in The Cask of Amontillado?

Why do you consider Montresor an unreliable narrator? The phrase you quote in your question suggests that the story is presented as a letter written by Montresor to some unknown friend. Presumably, Poe has gotten possession of it and translated it into English. It is similar in this respect to Poe's "A Manuscript Found in a Bottle." By establishing that "The Cask of Amontillado" is addressed to someone who knows him well, Poe can skip a lot of detailed explanations, including the nature of the "thousand injuries of Fortunato." Montresor may not be unreliable but just able to leave out a lot of expository detail because he is addressing an intimate acquaintance. This letter was written fifty years after the murder it describes. What does Montresor write that is not reliable?

What can we infer about Montresor's social position and his reliability as a narrator in "The Cask of Amontillado"?

In Edgar Allan Poe's short story "The Cask of Amontillado," one piece of evidence that Montresor is an unreliable narrator concerns his very motive for undertaking the tasks in the story. Montresor opens the story by claiming, "The thousand injuries of Fortunato I had borne as I best could," meaning that Fortunato is guilty of injuring him in a thousand different ways, perhaps financially. Montresor further adds the statement, "... but when he ventured upon insult I vowed revenge," meaning that when Fortunato added insult to injury, Montresor decided he must take revenge.

The very fact that Montressor is vengeful proves that he is an unreliable narrator. To be a reliable narrator, one most be objective; one must view the world from an objective standpoint, meaning a standpoint not influenced by one's personal feelings, prejudices, or biases. An unreliable narrator views the world from a subjective standpoint, meaning a standpoint influenced by personal feelings, prejudices, etc. Since we know Montresor is seeking revenge, we know that he is being driven purely be his emotions, making his viewpoint subjective and himself an unreliable narrator.

Further evidence concerns the fact that the story makes it unclear as to whether of not Fortunato is truly a bad guy. In fact, Montresor describes Fortunato as "a man to be respected and even feared," which calls into question the evilness of Fortunato's character, making us wonder if he really is a character who deserves the fate Montresor has inflicted upon him. By the end of the story, the reader is inclined to think, "no, Fortunato does not deserve such a fate," which makes the ending seem extremely tragic.

What can we infer about Montresor's social position and his reliability as a narrator in "The Cask of Amontillado"?

One thing that seems clear is that Montresor is a well educated and intelligent individual. Readers get a good bit of support for this evaluation already within the first paragraph. The vocabulary that he uses to explain and justify his revenge motive is quite highbrow and not something that an uneducated miscreant would use.

A wrong is unredressed when retribution overtakes its redresser. It is equally unredressed when the avenger fails to make himself felt as such to him who has done the wrong.

The fact that Montresor is able to plan and pull off his murder scheme also indicates that he is quite intelligent as well. He's sadistic for sure, but there's no doubt he's smart. Related to that intelligence is the fact that Montresor knows how to manipulate people. He knows exactly what he needs to say to Fortunato to get him to come into the catacombs. Montresor knows that the amontillado will be irresistible.

Readers also get some solid information that Montresor is quite wealthy. He speaks about enjoying wines, but that doesn't necessarily mean he's rich; however, Montresor admits to his readers that his taste palette is experienced with vintage Italian wines, and he buys them in large quantities whenever he can. He is financially well enough off to afford better than the bargain brand wines, and his home is large enough to have catacombs of storage.

In this respect I did not differ from him materially: I was skillful in the Italian vintages myself, and bought largely whenever I could.

Is Montresor an unreliable narrator in "The Cask of Amontillado"? Could he have imagined the injuries and insult, or even the entire story?

I don't think Montresor is as unreliable as he could be.  He is a murderer and allows his pride to rule him, certainly, but I don't think he is mentally unstable beyond his pride.  Montresor says that Fortunato's weak point is his pride, which is ironic because it also seems to be his own, and he does provide evidence to support this.  For one, Fortunato is too proud to miss an opportunity to prove Montresor wrong.  For all Fortunato knows, Montresor is quite willing to find the other wine expert in town, Luchesi, but Fortunato will not hear of it.  He asks, "Amontillado?  A pipe?  Impossible!  And in the middle of the carnival!"  Then, he says that "Luchesi cannot tell Amontillado from Sherry."  Later, he even calls Luchesi "an ignoramus."  In other words, he is certain that Montresor has overpaid for the wine, and he feels himself to be a far superior judge of wine to Luchesi as well.  If he weren't so proud and so eager to prove that Montresor has been played for a fool, he would have remained safely above ground.  As is, he is willing to compromise his own health in order to satisfy his pride.  

Later, when the two men are within the Montresor family vaults, below ground, Fortunato

laughed and threw [an empty] bottle upwards with a gesticulation [Montresor] did not understand. . . .  He repeated the movement.  "You do not comprehend?" he asked.  "Not I," [Montresor] replied.  "Then you are not of the brotherhood."  "Yes, yes," [Montresor] said, "yes, yes." [And Fortunato declared,] "You? Impossible!  A mason?"

Fortunato even demands a sign that Montresor is a member of this elite organization.  In other words, then, Fortunato attempts to reassert his superior social standing by referencing his membership in this sacred brotherhood and by pointing out that Montresor is not a part of the club.  It seems designed not to see if Montresor really is a member but rather to make Montresor feel less important than Fortunato.

Therefore, Montresor does provide some proof of Fortunato's terrible pride (he is willing to sacrifice his health to prove Montresor wrong), as well as Fortunato's intent to insult him (by rubbing his nose in the fact that Fortunato is a mason and Montresor is not).  This certainly doesn't provide a good reason to murder someone, but there is some indication that it isn't all in Montresor's imagination.

Is Montresor an unreliable narrator in "The Cask of Amontillado"? Could he have imagined the injuries and insult, or even the entire story?

Montresor is an unreliable narrator, yes, because he is clearly mentally unstable.  He cannot be trusted.  In addition, there is no evidence that Forunato did, in fact, insult or do anything of great harm to Montresor at all in the story.  Poe provides no details.  Because the narrator is unreliable, we cannot trust him when he says that Fortunato has wronged him.  We do not know if this is true at all.  EVen if Montresor HAD provided evidence, we still could not trust him because he is an unreliable narrator.  For all we know, he could be making it up.  It does not take long to look for evidence to support the fact that Montresor cannot be trusted and is unreliable because of his murderous plot and because he is emotionless and remorseless for what he is doing.  He has no regrets and is happy with his plans.

Is Montresor an unreliable narrator in "The Cask of Amontillado"? Could he have imagined the injuries and insult, or even the entire story?

"The Cask of Amontillado" is Montressor's story. He is a man who tells the story of his revenge on his apparent nemesis, Fortunato.  He does claim that Fortunato has committed a thousand injuries until he (Montressor) has had enough.  We either have to believe him and take him literally at his word, or we have to test his reliability as a narrator and see those thousand injuries as hyperbole (exaggeration).  I'll point out a few things, you watch for exaggerations, and you can make your own judgment from there.

Montressor claims a thousand injuries, yet when he is offered just one "insult," he is ready to seek revenge--to the death. Any exaggeration there?

When Montressor meets Fortunato for the first time at Carnival, he says this:

I was so pleased to see him, that I thought I should never have done wringing his hand.

This is a detail that doesn't really matter, yet Montressor feels the need to exaggerate even about a handshake.

Once Montressor has gotten the coughing Fortunato into the underground vaults, he says the following:

"Come," I said, with decision, we will go back; your health is precious. You are rich, respected, admired, beloved; you are happy as once I was. You are a man to be missed. For me it is no matter. We will go back; you will be ill and I cannot be responsible.

This is an obvious exaggeration used to make continue luring his enemy into the catacombs of his villa. 

If you've read the entire work, you know that Montressor is not above saying anything he needs to in order to get what he wants and convince you he's not really insane, just protecting his family honor (another exaggeration, of course). 

Perhaps the most compelling argument that whatever Fortunato did was minimal or even inadvertent (accidental) and completely one-sided is the fact that Fortunato doesn't even really hesitate to go with Montressor.  Surely an enemy worthy of murdering will have shown some real animosity, but that doesn't happen in this story. 

Your assessment is valid.  Follow this train of thought and you can make a strong and effective argument.

Is Montresor a reliable or unreliable narrator in The Cask of Amontillado?

One view is that Montresor is an unreliable narrator because of his deranged attitude and behavior toward Fortunato. Another view might be taken wherein Montresor's behavior toward Fortunato is separated from the narrative he reports about his behaviors and about events leading up to Fortunato's entombment. With this separation of behavior from narrative of behavior, it might be argued that, although Montresor is maladapted in his social expectations, responses and actions, he is a clear and reliable reporter, or narrator, of those expectations, responses and actions.

By this argument, we accept that Montresor's report of offenses against him by Fortunato is accurate, although filtered through a maladapted social lens. For example, Fortunato, a Freemason, might not have given enough respect and deference to Montresor's ancient and noble ancestral origins and accomplishments; Fortunato may have been a modern man who gave respect to merit above ancestry. To Montresor, this may equal to a "thousand injuries."

Further, by this argument, we accept that Montresor performed the chilling deed just as he reports having performed it. We have to wonder, then, to whom he is narrating his chilling tale "the half of a century" after he "re-erected the old rampart of bones" against Fortunato's unfortunate tomb.

Some suggest he is telling his narrative to a psychiatrist or a police official. It may also be suggested that he is telling his tale to an heir, a family member to whom the character of fortune's benefactor is being precisely, even vainly drawn: an heir to whom Montresor is baring his soul while expecting it to be admired (for upholding the family honor).

So, by this argument--the argument that Montresor is socially maladapted but perceptually acute and accurate--it may be said that Montresor is a reliable narrator giving an incomprehensible reality to a horrific tale of "vowed revenge" and "punishment with impunity."

I vowed revenge. You, who so well know the nature of my soul, will not suppose, however, that I gave utterance to a threat. At length I would be avenged; ... the very definitiveness with which it was resolved precluded the idea of risk. I must not only punish but punish with impunity. A wrong is unredressed when retribution overtakes its redresser. It is equally unredressed when the avenger fails to make himself felt as such to him who has done the wrong.  

Is Montresor a reliable or unreliable narrator in The Cask of Amontillado?

Many people have called Montresor an "unreliable narrator." Some seem to think Montresor is telling his story to them. There are multiple ways to look at this issue, but one can definitely make the case that Montresor is a reliable narrator. Poe makes it clear from the beginning that this is a confidential communication to one single individual whom Montresor has known for many years. He addresses this person as "You, who so well know the nature of my soul." If he is unreliable, he is not intentionally so. If the reader fails to understand something Montresor says or writes, that does not mean the confidant, or confidante, does not understand it perfectly. If Montresor is "unreliable," it can only be because he does not understand himself; he is not trying to deceive the confidant or confidante, and there is no one else he could have been trying to deceive.

So, where is the evidence of unreliability? Most people point to the thousand injuries plus an insult. Montresor is certainly unreliable in what he says to Fortunato, but he knows he is being intentionally deceptive. Why does it seem unreliable to say that he received a thousand injuries from his victim? Surely the recipient has heard from Montresor a number of times over the fifty years before receiving this strange confession. If the reader does not know the nature of at least some of the injuries, the person who reads the confession must surely have heard about some of them in all that time. If they had not been corresponding for fifty years, Montresor would not be so sure he could trust the other person with this incriminating revelation. He considers the other man, or woman, a person who knows all about him, who knows the nature of his soul. Is this also supposed to be unreliable? Was Montresor making a big mistake in trusting this other person with such information? That seems unlikely because he had taken such great precautions, not only to commit the murder, but to do so with what he calls "impunity." No one would suspect him of having anything to do with Fortunato's strange disappearance because everyone thought they were the best of friends. Montresor repeatedly refers to his victim as "my friend," "my good friend," and "my poor friend" even when he is leading him to his death. He has conditioned himself to think of Fortunato as his friend and always to speak of him as his friend, even as his good friend. He should be above suspicion, and he would have been the one who showed the most concern about Fortunato's whereabouts for the longest time. The reader can only call Montresor "unreliable" if he assumes Montresor is addressing him, but Poe has invented a narrative device that enables him to leave out a plethora of background information in order to focus on the dramatic aspect of the narrative.

Why might the author have chosen Montresor as the narrator in "The Cask of Amontillado"?

Poe chose Montresor as his narrator because he is a madman, and madmen make good narrators.

Madmen are unreliable narrators, because they think they are clever and doing the right thing.  Montresor is an example of this.  He thinks that killing Fortunato is the right thing to do because he has insulted him in some way, even though the insult is likely small and imagined.

The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge. You, who so well know the nature of my soul, will not suppose, however, that I gave utterance to a threat. At length I would be avenged…

Although Montresor would surely tell you he is as sane as you or I (if he were a real person), he clearly is not playing with a full deck.  You do not murder someone because he has insulted you.  If Fortunato had really done something to Montresor, he would not have turned his back on him or gone into a crypt with him.  The fact that Fortunato suspected nothing is evidence that the “injuries” and insults are imagined or minor.  Montresor is nuts.

Why choose someone who is crazy to tell your tale?  Well, crazy people are more interesting. This story would have been pretty boring if it was about one friend showing another friend a cask of wine and asking him his opinion of it. I doubt that story would be read a hundred years later. No, a real story has to have a hook. A suspenseful story is when one of those men is plotting the murder of the other.

I must not only punish but punish with impunity. A wrong is unredressed when retribution overtakes its redresser. It is equally unredressed when the avenger fails to make himself felt as such to him who has done the wrong.

Did I mention that not only does Montresor have to kill Fortunato, but he also has to get away with it? So he gets rid of his nosy servants (he tells all of his servants to make sure they stay home because he won’t be there, knowing they will leave), and goes out on the town for carnival.

Montresor is a good observer of human nature, as all madmen seem to be. Consider how well he knew his servants! He also knew that Fortunato’s guard would be down at carnival time, and others' would, too. He even lowers Fortunato's defenses by suggesting that Fortunato leave, that he will get someone else to look at the wine.

“My friend, no; I will not impose upon your good nature. I perceive you have an engagement. Luchesi—”

“I have no engagement;—come.”…

“Let us go, nevertheless. The cold is merely nothing. Amontillado! You have been imposed upon. And as for Luchesi, he cannot distinguish Sherry from Amontillado.”

Montresor knows that if he suggests that someone else should look at the wine, then Fortunato will want to look at it. It’s human nature. He does not want to miss out.

Another reason Montresor is a good narrator is because he thoroughly creeps the readers out, but he makes us look at ourselves. Does Montresor have a conscience? After he bricks Fortunato in, and he starts to realize what has happened to him, he panics. He screams to Montresor to let him out, hoping it is all a sick joke.

Montresor does not let him out, but does he have a conscience after all? He calls to Fortunato—to make sure he is dead. Yet, look at his reaction.

My heart grew sick; it was the dampness of the catacombs that made it so. I hastened to make an end of my labour. I forced the last stone into its position; I plastered it up.

You can interpret this as an attack of conscience, even though Montresor attributes it as the catacombs. It is revealed that he is looking back on the incident, which implies grief and remorse, because “half of a century” has passed. The last words of the story, “Rest in peace!” can be interpreted ironically, or genuinely. The entire thing seems like an attempt at a justification, not to the reader, but to himself.

Can you be mad and have a conscience? Absolutely. In fact, psychopaths often feel that they are compelled to commit heinous acts, and then feel remorse afterwards. Sociopaths do sometimes commit their horrible murders without caring. Which one is Montresor? It's up to you to determine.

It could be that Montresor has no conscience, and the last sentence is ironic. However, he could actually feel some sympathy and remorse for what he has done. He killed with impunity. That was what he wanted. There is no reason not to feel remorse as well for Fortunato. In Montresor's mind, he deserved to die. Yet Montresor can still be sad that he is dead.

The ending of the story is open to interpretation, depending on your view of human nature.  What is not open to interpretation is that Montresor is mad.  Poe chose him because madmen make good murderers, and murder makes a good story.  We like to read about murder because it is exciting, and because stories like this tell us more about ourselves.  In this story, we learn to be careful who we trust.  Sometimes people who seem normal are far from it.

What indicates that Montresor is an unreliable narrator in The Cask of Amontillado?

We are lead to believe that Montressor is mad because he gives no reason or motive for his revenge.  He says that Fortunato had born him a thousand injuries, but he cannot give any specific example that warrants murder.  More, Fortunato does not suspect his scheme at all.  This suggests that Montressor is more than just a little sensitive, to the point of paranoia and schizophrenia (detachment from reality).

Also, Montressor is able to remember the entire story as if were yesterday, when--in fact--it has been over 50 years.  This suggests that Montressor has played and re-played the revenge in his mind, taking satisfaction in every last detail--to the point of megalomania.

One other scenario is that none of this ever happened: Montressor may have invented the entire plot!  We cannot be sure.  Perhaps this is the most disturbing.

Lastly, Montressor takes joy in suffering and death.  He even mentions his work in connection with "the love of God."  Look at the end for clues:

“Ha! ha! ha!—he! he! he!—a very good joke, indeed—an excellent jest. We will have many a rich laugh about it at the palazzo—he! he! he!—over our wine—he! he! he!”

“The Amontillado!” I said.

“He! he! he!—he! he! he!—yes, the Amontillado. But is it not getting late? Will not they be awaiting us at the palazzo, the Lady Fortunato and the rest? Let us be gone.”

“Yes,” I said, “let us be gone.”

“For the love of God, Montresor!”

“Yes,” I said, “for the love of God!”

But to these words I hearkened in vain for a reply. I grew impatient. I called aloud—

“Fortunato!”

No answer. I called again—

“Fortunato!”

No answer still. I thrust a torch through the remaining aperture and let it fall within. There came forth in return only a jingling of the bells. My heart grew sick; it was the dampness of the catacombs that made it so. I hastened to make an end of my labour. I forced the last stone into its position; I plastered it up. Against the new masonry I re-erected the old rampart of bones. For the half of a century no mortal has disturbed them. In pace requiescat!

What is one reason that indicates Montresor is an unreliable narrator?

In short, having to decide between your answers, c or d, I would choose c. However there is more to consider than that.

"The Cask of Amontillado" is narrated in the first person and Montresor, admits in the first sentence that he will have revenge. He speaks directly to the reader as "you" assuming that the reader knows his soul. Montresor's voice is so even--not strained or emotional--he tells his story straightforwardly. However, he leaves in what he wants the reader to know and also leaves out what he does not want the reader to know. This is the critical point of the first person narrative--it is manipulative. The reader cannot decide for herself or himself what to believe about a character because it is a monologue. His feelings are hidden. (That is suspicious for a person seeking revenge.) The most terrifying moment in the story is when Fortunato knows he is being sealed up. However, Montresor is calm. He says, "I had scarcely laid the first tier of the masonry when I discovered that the intoxication of Fortunato had in a great measure worn off. The earliest indication I had of this was a low mourning cry from the depth of the recess. It was not the cry of a drunken man. There was then a long and obstinate silence. I laid the second tier, and the third, and the fourth."

In this story Poe presents the material without any interpretation. What makes this story so dark and sinister is the lack of emotion of the narrator.

If there ever were a sociopath, it would be Montresor.

What three details make Montresor an "untrustworthy narrator" in "The Cask of Amontillado"?

An untrustworthy narrator can be identified by several key elements;

• The narrator's perspective and opinions are the only one we are exposed to.
• The narrator fails to give details about an important event.
• Opinions are represented as facts.

Generally speaking, an unreliable narrator is one who provides us with incomplete or nonexistant answers to questions that are obviously important; in The Cask of Amontillado, this question might be "what did Fortunato actually DO to Montresor that merits burying him alive?

Much of Montresor's unreliability reveals itself early in the story;

1. "The thousand injuries of Fortunato I have borne as best I could". Montresor does not tell us what these injuries are.
2. "You, who so well know the nature of my soul," we do not know Montresor, but as the narrator, he is assuming that we understand and agree with him.
3. "For the half of a century no mortal has disturbed them." This sentence appears at the end of the story and makes it clear that this entire affair took place long ago; it is unclear exactly how old Montresor is at this point, but we might assume anywhere from 70 to 100; this casts doubt on the timeline as well as his memory.

What three details make Montresor an "untrustworthy narrator" in "The Cask of Amontillado"?

As a first person narrator making what is probably a death bed confession fifty years after the fact, Montresor is telling the story in a way most likely to justify what he has done. We have nobody else's version of the tale with which to compare what Montresor tells us. Therefore, we have to take his word about what happened. This is the word of someone capable of murdering a rival in heinous way by walling him up in a catacomb and leaving him to die, so one has every reason to suspect that this narrator is mentally unstable.

Further, Montresor never specifies what were the "thousand injuries" he claims Fortunato perpetrated against him. That there were so many leads one to believe they must have been small. But if that is true, we wonder why Montresor reacted in such an extreme way.

All of this uncertainty, along with the barbaric nature of the crime, undermines Montresor's reliability as a narrator.

What three details make Montresor an "untrustworthy narrator" in "The Cask of Amontillado"?

Montresor never mentions even one of the "thousand injuries" that Fortunato has supposedly inflicted upon him: 

The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge. 

Montresor also does not detail what the "insult" was. The reader could simply take Montresor's word for it, but that is an assumption. A narrator establishes himself as a reliable source by providing explanations and reasons for his statements. Montresor never does this with the injuries and insults. 

Montresor also brags about his ability to hide the truth: 

It must be understood that neither by word nor deed had I given Fortunato cause to doubt my good will. 

Montresor proves how he can lie to and manipulate Fortunato. Since he is directly addressing the reader, who's to say he is not being a manipulative narrator as well? 

Some have suggested that Montresor's French name implies that he is new to Italy and therefore, he would have no Italian coat of arms. When Fortunato says he doesn't remember Montresor's coat of arms, this might be a minor insult because Montresor would not have a coat of arms. And note the motto: "Nemo me impune lacessit." This basically means "no one can harm me unpunished." It seems possible that Montresor could have made this up to underscore his feelings of vengeance. We can only guess what else he may have made up. 

Can we trust Montresor's account in the story of "The Cask of Amontillado"?

We do not know that the concept of revenge is only in the mind of Montresor. Some readers believe he has no valid reason for wanting revenge, while others believe he has suffered a thousand injuries at the hands of Fortunato. We are pretty much forced to rely on Montresor because he is narrating events that only he knows about. The story of the Amontillado is not "real" in more than one sense. First, it was created by Edgar Allan Poe. It never really happened. The characters never really existed except in Poe's imagination. Second, one of those characters invented the cask of Amontillado in order to lure the other character down into his catacombs. There was no cask of Amontillado. Does it make any difference whether Montresor has a valid reason for wanting revenge or whether he only imagines that Fortunato has injured him? Montresor wants to murder Fortunato, and he succeeds in doing so. That is what the story is about. The only reason there could be for suspecting that Montresor does not have a valid excuse for committing the murder would be that Poe fails to give examples of the "thousand injuries" Montresor thinks he has suffered. Poe made a decision not to elaborate on those injuries, but he probably wanted his readers to believe they were real injuries and not imaginary. You seem to be suggesting that Montresor made up the entire story about the murder and that none of it really happened. This gets pretty complicated, since it is quite true that none of it really happened. Did Poe make up a story that never happened about a man who made up a story that never happened? This is a little too post-modernistic for the time.