The following quotation from Mill's The Subjection of Women demonstrates the extent to which sympathy was thought of as a learned, cultivated force which was crucial for the existence of social ties and hence for the healthy functioning of "modern" society:
"We are entering into an order of things in which justice will again (referring to the Greeks) be the primary virtue; grounded as before on equal, but now also on sympathetic association; having its root no longer in the instinct of equals for self protection, but in a cultivated sympathy between them; and no one being now left out, but an equal measure being extended to all...the true virtue of human beings is fitness to live together as equals; claiming nothing for themselves but what they as freely concede to everyone else; regarding command of any kind as an exceptional necessity, and in all cases a temporary one; and preferring, whenever possible, the society of those with whom leading and following can be alternate and reciprocal...Citizenship, in free countries, is partly a school of society in equality; but citizenship fills only a small place in modern life, and does not come near the daily habits or inmost sentiments. The family, justly constituted, would be the real school of the virtues of freedom. It is sure to be a sufficient one of everything else. It will always be a school of obedience for the children, of command for the parents. What is needed is, that it should be a school of sympathy in equality, of living together in love, without power on one side or obedience on the other."
Additionally, Mill gives that citizenship only fulfills one part of educating people as to how they should function in society, and that the family fulfills the part of educating "inmost sentiments." This foregrounds the importance of family to Mill's vision of the healthy, functional society.
More generally, the entire quotation underscores the need to consider "sympathy" in relation to larger social relations in the nineteenth-century, and something associated with deliberate cultivation rather than with unrestrained, emotional outpouring. The sympathy which Mill talks about above is in no way similar to the "sympathy" that might have been ascribed to the tear-filled, dramatic displays of charity often associated with women's groups beginning in the 1830's.
Wilde in "The Critic as Artist" defines an alternative "sympathy of thought" which is better than the "sympathy of suffering" which is supposed to motivate social action. "Sympathy of thought" is a Paterian concept which advocates finding those who match you in (aesthetic) temperament throughout the ages. Seeking this kind of sympathy is a different kind of reform which builds on a genealogy of what has been thought in all of human history, envisioning that making these kinds of genealogical connections will have a more lasting impact on the world.
Rachel Ablow, Marriage of Minds: Reading Sympathy in the Victorian Marriage Plot
-Sympathy is a psychic structure which enabled the production, consolidation, or redefinition of a subject
-18th century sympathy usually seen as the basis for civic life, social ties (Hume, Smith)
-Ablow reads the removal of sympathy to a private sphere (gendered feminine, domestic) as no less engaged with the health of civic life (see above quote from Mill) - sympathy in marriage was a corrective, tempering influence on the self-made man involved in the market
-Novels often had this kind of a corrective, tempering influence analogous to the role of the domestic, private sphere in marriage.
-Dickens was repeatedly figured as having a "wifely" relationship to his readers