I believe Dickens is suggesting that the only way to keep one’s sanity during injustice, is to willingly let some sanity go. The only sane characters in the Chancery Court are cruel at worst, coldly unfeeling at best. Mr. Tulkinghorn is the primary example of the cruelty, Ms. Flite of the sort of insanity that preserves human kindness in the fog of Chancery. Most of the other characters involved in the Chancery case fit one of these two extremes. Mr. Jarndyce is a “a little M, you know!” as Ms. Flite likes to call Mr. Krook. But his panic about gratitude and his obsession with the easterly winds makes him merely eccentric and more kindly. We feel about him much as we feel about Ms. Flite. The response toward cruelty is usually reserved for the lawyers, but Guppy is an exception. He is also “a little M,” though. Two characters attempt to battle the insanity and injustice of Chancery with reason, but they fail.
Gridley and Richard are two who do not elect either gentle insanity or utter cruelty. Gridley defends his angry, insistent approach to Chancery so: “if I took my wrongs in any other way, I should be driven mad! It is only by resenting them, and by revenging them in my mind, and by angrily demanding the justice I never get, that I am able to keep my wits together. It is only that!” (4884). Notice that Gridley cares much more about “keeping his wits” than Ms. Flite or Mr. Jarndyce. Richard too, is not willing to let “reason and justice” go, though Mr. Jarndyce laments that Chancery is, “Unreason and injustice at the top, unreason and injustice at the heart and at the bottom, unreason and injustice from beginning to end…” (18376). If one is to encounter injustice, one must do it with a modified unreason, apparently.
A possible cause for this lies in this cryptic riddle from the narrator: “Injustice breeds injustice; the fighting with shadows and being defeated by them necessitates the setting up of substances to combat” (12552). The injustices of chancery have been weaving such a fog of shadows for so long a time, that the fog is all that’s left. To take a solid reason and corporeal justice into this fog can only be fatal for those who maintain their reason. Gridley and Richard do not survive the novel because they demand justice from shadows, and when the case simply evaporates in the end, Richard senses a loss not just of the money and the inheritance, but also the sort of loss that Don Quixote would experience were he to come to his senses in the middle of battling windmills. It is the loss of an ideal that never existed.
But Ms. Flite is able to release her birds because she has responded to shadows by becoming a shadow of her former self. While she releases her reason, she maintains her kindness and good humor – possibly the best parts of her humanity. Jarndyce and Jarndyce are no more, but Ms. Flite and Mr. Jarndyce remain.