C. Auguste Dupin discussing Dupin's method in the light of Charles Sanders Peirce's logic of making good guesses or "abductive reasoning," Nancy Harrowitz first quotes Poe's definition of analysis and then shows how "Poe the semiotician is running the gamut of possibilities here—inferences, reasoning backwards, visual, sensual and aural signs, reading faces. Playing cards with the man would have been an interesting experience." There is considerable controversy about the philosophical nature of Dupin's method. According to biographer Joseph Krutch, Dupin is portrayed as a dehumanized thinking machine, a man whose sole interest is in pure logic. However, Krutch has been accused elsewhere of
Louis Ellies Dupin both in his invectives against the "haughty critics" who inclined to rabbinism and the errors of Socinus. Although Dupin spoke favourably of Arnauld and signed the "Cas de conscience", he was not a Jansenist. Rather, on these matters he shared the opinions of Launoy, who "had found a way to be at once both demi-Pelagian and Jansenist". Dupin was pre-eminently a Gallican. It was probably on this account that Louis XIV had him exiled to Châtellerault, on the occasion of the "Cas de conscience". Dupin retracted and returned, but his chair in the College of France was irretrievably lost. Later