As an emotion of the mind will express itself through any covering of the body, so the paleness which his situation engendered came through the brown upon his cheek, showing the soul to be stronger than the sun. (2.2.41)
Charles Darnay’s very body seems to testify to his innocence in the English court.
"If you knew what a conflict goes on in the business mind, when the business mind is divided between good-natured impulse and business appearances, you would be amused, Mr. Darnay." (2.4.22)
Oscillating between businessman and human being, Mr. Lorry often finds that his good heart becomes the source of most of his worries.
He had that rather wild, strained, seared marking about the eyes, which may be observed in all free livers of his class, from the portrait of Jeffries downward, and which can be traced, under various disguises of Art, through the portraits of every Drinking Age. (2.5.12)
If Sydney operates under the assumption that he’s naturally fitted for his role, his "lion" (Mr. Stryver) is described by the narrator as equally fated for the role he plays.
At length the jackal had got together a compact repast for the lion, and proceeded to offer it to him. The lion took it with care and caution, made his selections from it, and his remarks upon it, and the jackal assisted both. When the repast was fully discussed, the lion put his hands in his waistband again, and lay down to mediate. (2.5.27)
Sydney does all the thinking while Stryver, his "friend," takes all the credit for being a brilliant legal mind. Depicting this relationship as similar to that of jackals and lions furthers the sense that this is a natural (and unchangeable) order.
He knew very well, that in his horror of the deed which had culminated the bad deeds and bad reputation of the old family house, in his resentful suspicions of his uncle, and in the aversion with which his conscience regarded the crumbling fabric that he was supposed to uphold, he had acted imperfectly. He knew very well, that in his love for Lucie, his renunciation of his social place, though by no means new to his own mind, had been hurried and incomplete. (2.24.58)
Darnay’s sudden decision to return to France is based upon a strong sense of responsibility for his family’s actions. To his mind, inaction can be as immoral as bad actions.
His latent uneasiness had been, that bad aims were being worked out in his own unhappy land by bad instruments, and that he who could not fail to know that he was better than they, was not there, trying to do something to stay bloodshed, and assert the claims of mercy and humanity. With this uneasiness half stifled, and half reproaching him, he had been brought to the pointed comparison of himself with the brave old gentleman in whom duty was so strong. (2.24.61)
The type of introspection that Darnay shows at this moment marks him as our "hero." He’s just so… good. It’s interesting to note that we don’t get a similar moment of reflection when Carton contemplates heroic action.
No fight could have been half so terrible as this dance. It was so emphatically a fallen sport—a something, once innocent, delivered over to all devilry—a healthy pastime changed into a means of angering the blood, bewildering the senses, and steeling the heart. Such grace as was visible in it, made it the uglier, showing how warped and perverted all things good by nature were become. (3.5.32)
Multiple descriptions of mob mentality emphasize the ways that just about anyone can get "warped" by the sweeping violence of the revolution.
In seasons of pestilence, some of us will have a secret attraction to the disease—a terrible passing inclination to die of it. And all of us have like wonders hidden in our breasts, only needing circumstances to evoke them. (3.6.6)
And just in case you thought this was a self-contained history, Dickens makes sure you know that the French Revolution is also a cautionary tale. We all have the capacity to become as violent and irrational as the mob of revolutionaries.
Miss Pross recalled soon afterwards, and to the end of her life remembered, that […] there was a braced purpose in the arm and a kind of inspiration in the eyes, which not only contradicted his light manner, but changed and raised the man. (3.8.53)
Sydney’s choice to sacrifice himself is made all the more honorable because he doesn’t choose to share his plans with anyone. Instead of his own reflections, we get observations from Miss Pross.
"I hope, sir," pleaded the abashed Mr. Cruncher, "that a gentleman like yourself wot I've had the honour of odd jobbing till I'm grey at it, would think twice about harming of me, even if it wos so—I don't say it is, but even if it wos. And which it is to be took into account that if it wos, it wouldn't, even then, be all o' one side. There'd be two sides to it." (3.9.7)
Mr. Cruncher engages in some fine moral relativism here. Sure, it’s bad that he digs up graves. Then again, between doctors and lawyers and undertakers, just about everyone else makes some money off of dead bodies, don’t they?