Edgar Allan Poe: The Purloined Letter

0. The Purloined Letter (continued)

"It is," said Dupin; "and, upon inquiring, of the boy by what means he effected the thoroughidentification in which his success consisted, I received answer as follows: '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.' This response of the schoolboy lies at the bottom of all the spurious profundity which has been attributed to Rochefoucault, to La Bougive, to Machiavelli, and to Campanella."

"And the identification," I said, "of the reasoner's intellect with that of his opponent, depends, if I understand you aright, upon the accuracy with which the opponent's intellect is admeasured."