Here's a paper I wrote about Middlemarch in 1998:
In the epigraph to chapter 64 of Middlemarch, the two gentlemen discuss power and responsibility. Rejecting the notion that power carries with it a complete culpability for its consequences, the passage instead suggests that as "cause is not cause/ Unless effect be there; and action's self/ Must needs contain a passive. So command/ Exists but with obedience" (616). In order to have power, one must have a cooperative body over whom to exercise it; and that cooperation renders each party equal for that relationship's outcomes. Not only then is power is shared between those in the dominant and submissive roles, but thay symbiotic relationship must establish itself first in order for any power to exist. An individual, regardless of his position or intentions, cannot effect any changes until these interpersonal connections take shape. Lydgate, who has an ardent wish, like Dorothea, for "some active good," believes however naively, that he already possess the power to do it. If we accept the epigraph's assertions about power, though, the important question in regard to Lydgate becomes whether or not he is able to choose the relationships in which he becomes emotionally invested. If these relationships will shape the scope of his power, then those choices will finally determine their capacity to work that "active good."
If he does, in fact, have the ability to choose his relationships, by the end of the novel it becomes quite clear that he has made a rather limiting choice. In the chapter in which the epigraph appears, we discover the full extent of Lydgate's limitations. Once "determined to live aloof" from the "abject calculations" that dictate lesser men's actions, he finds that his marriage to Rosamond has forced him to emulate them (630). This appears to him to be the consequence of Rosamond's obstinacy, "which would not allow any assertion of power to be final" (628). In marrying Rosamond, we see that he has agreed implicitly that his ability to make her happy predicates his ability to make others happy, to contribute "active good" to the world. When she suggests to him that "she had been deluded with a false vision of happiness in marrying him," he is forced not only to acknowledge that he is not her superior, but that he is not superior to those lesser men and their "abject calculations" (629). The good that he thought would come from his superiority, the intellectual freedom to pursue his medical inquiries, vanishes.
We may blame Rosamond for this, but then we would make the same mistake Rosamond herself makes later when Rosamond imagines that perhaps Will Laidislaw would have made her a better husband. "No notion could have been falser than this," our narrator instructs us, "for Rosamond's discontent in her marriage was due to the conditions of marriage itself, to its demand for self-suppression and tolerance, and not to the nature of her husband" (716). Rosamond, in her typically egoistic fashion, mistakes a structurally flawed scenario for a unique, particular one, which leads her to believe that a change of those particulars will cure her of her torpor: as the narrator explains, "the easy conception of an unreal Better had a sentimental charm which diverted her ennui" (716). Lydgate's frustration parallels this. His temptation is to hold Rosamond accountable for a situation where power and responsibility really reside in the entire structure of their relationship. Like Rosamond, Lydgate is frustrated by the "conditions of marriage itself," particularly the condition that demands that relation take priority over all other social relations. Lydgate's dream of medical advancement becomes the "unreal Better" that he dreams of for distraction, with the real Better being the satisfaction of his marital vow.
Dorothea, in her climactic meeting with Rosamond, addresses this very issue: "Marriage is so unlike everything else. There is something awful in the nearness it brings. Even if we loved some one better than -- those we were married to, it would be no use. . . . Marriage drinks up all our power of giving or getting any blessedness in that sort of love" (758). Lydgate does not love a "some one" better, but his medical ambition is the metaphoric other woman he must renounce. That love of his is a vanity, as much as Rosamond's love for Will is, or Dorothea's love for Causabon, which she is speaking of here, had been, for that matter. When Dorothea urges the renunciation of these loves, she essentially urges the surrender of one's vanity, which, we are led to believe, is the real impediment to achieving any "active good." The institution of marriage, then, allows for this necessary renunciation, allows for this pleasant martyrdom, the highly localized amelioration it permits, and little else. Instead of pursuing his discoveries, Lydgate must "accept his narrowed lot with sad resignation," carrying the "burthen" of Rosamond "pitifully" (761). Though this resolution has the seemingly curious effect of creating a chain of pity, which, in terminating with Rosamond's self-pity (Eliot's narrator pities Lydgate, who pities Rosamond, who pties herself), seems to aggrandize it; it also allows for Lydgate a martyrdom, which, too, is self-pity, under a more respectable name.
This may explain why, in the novel, the conditions of marriage appear beyond question. Dorothea never questions the idea that allowing a marriage to fail is tantamount to "murder," a crime whose guilt obviates all else ("everything else is gone," she tells Rosamond as she describes moribund marriages). Marriage provides a fixed point, an unquestionable moral certainty from which all other moral beliefs may emanate. Without some such absolute, the sacrifices one might make may always be relative, and may only amount to some more well-rationalized vanity supplanting the vanity one tries to renounce. Thus "everything else" depends upon it; without its sanctity, "everything else is gone." But if we reject that absolute, we find that idealistic vanity supplanted with pessimisstic martyrdom is no different than self-aggrandizement supplanted with self-pity, and "active good" outside the immediate circle of oneself remains impossible. The union of two people only seems to diminish both of them, and by extention, the intertwining of all souls with each other in the great social web reduces us all to the lowest common denominator of our decidely narrow mutual interests, the "abject calculations" and "the self-interested anxiety" that Lydgate deplores. The "growing good" we are supposed to have inherited by virtue of Dorothea's "hidden life" is the stultifying sense of guilt that accompanies any effort to shake off the ball and chain of our common, flawed humanity, figured in the inevitably flawed loves that bind us to each other.