Purloined Letter and Murders in the Rue Morgue

Honestly, never having read any of Poe's work except for an extremely long and difficult recitation of "The Raven" in 5th grade, I had rather pessimistic preconceptions of Poe's writing style. However, I was happy to find that Poe's writing was not inscrutable, but rather has a very clean flow with weird French and Latin words and phrases intermixed to keep me on my toes. It is definitely different that Doyle's work, but the duos of Narrator/Dupin and Sherlock/Watson do share some striking similarities; I look forward to reading more of Poe during my spare time. 

Overall, the most interesting passages were the longer, detailed-oriented explanations where Dupin displayed his analytical ability. For me, the most logical one was:

"They have no variation of principle in their investigations; at best, when urged by some unusual emergency --- by some extraordinary reward --- they extend or exaggerate their old modes of practice, without touching their principles. What, for example, in this case of D---, has been done to vary the principle of action? What is all this boring, and probing, and sounding, and scrutinizing with the microscope and dividing the surface of the building into registered square inches --- what is it all but an exaggeration of the application of the one principle or set of principles of search, which are based upon the one set of notions regarding human ingenuity, to which the Prefect, in the long routine of his duty, has been accustomed?" (504 The Purloined Letter). 

This explanation is a very concise way of explaining the importance of social game theory, the idea that the optimal strategy does not unilaterally strive for the goal, but also takes into account the strategies and pay styles of the other players. The Prefect is showcased as the perfect example of how people with inflexible conceptions of how to "win" the game will inevitably fail. This passage also implies that this inflexibility is created by hubris, for the Prefect and other policemen think that their intellect matches that of the criminal and want to catch the criminal with their "tried and true" methods. 

The most baldly tenable passage was: 

" 'When I wish to find out how wise, or how stupid, or how good, or how wicked is any one, or what are his thoughts at the moment, I fashion the expression of my face, as accurately as possible, in accordance with the expression of his, and then wait to see what thoughts or sentiments arise in my mind or heart, as if to match or correspond with the expression.' " (503 The Purloined Letter). 

This passage, spoken by the boy who won all the marbles, intends to explain why the boy was so good at analyzing his opponents and determining whether they would have "odd" or "even". Overall, while it is true that one can get some read of another person from understanding their micro expressions, it is unrealistic that such a tactic would be right 100% of the time. In The Murders in the Rue Morgue, Dupin astonishes the narrator by figuring out he is thinking about Chantilly by "reading" his expressions and body language from 15 minutes prior. The narrator's mode of thought contained 7 distinct points, of which Dupin would have needed to ascertain all to figure it out. Such a delicate deduction could not realistically be done using something as subjective as facial expressions, which makes Dupin's "method" limited, if not implausible. 

The most confusing passage for me was: 

"A novice in the game generally seeks to embarrass his opponents by giving them the most minutely lettered names; but the adept selects such words as stretch, in large characters, from one end of the chart to the other. These, like the over-largely lettered signs and placards of the street, escape observation by dint of being excessively obvious; and here the physical oversight is precisely analogous with the moral inapprehension by which the intellect suffers to pass unnoticed those considerations which are too obtrusively and too palpably self-evident." (508 The Purloined Letter). 

Honestly, I somewhat understood the part about mathematics and chemistry, but this reference to signs completely bewilders me. Are the novice and adept mentioned in the paragraph the shop-owners who make the signs, or the people who make the map for which the store names are placed? If the novice and adept are indeed map-makers instead of shopkeepers, then why would the mapmaker have any reason/incentive to favor some stores over others? I assume that last sentence is related to the intellectual missing the obvious, but why is that considered a "moral in-apprehension." I don't see any moral issue here at all.