Maggie Tulliver is the protagonist of The Mill on the Floss. When the novel begins, Maggie is a clever and impetuous child. Eliot presents Maggie as more imaginative and interesting than the rest of her family and, sympathetically, in need of love. Yet Maggie's passionate preoccupations also cause pain for others, as when she forgets to feed Tom's rabbits, which leads to their death. Maggie will remember her childhood fondly and with longing, yet these years are depicted as painful ones. Maggie's mother and aunts continually express disapproval with Maggie's rash behavior, uncanny intelligence, and unnaturally dark skin, hair, and eyes. Yet it is only Tom's opinion for which Maggie cares, and his inability to show her unconditional love, along with his embarrassment at her impetuosity, often plunges Maggie into the utter despair particular to immaturity.
The most important event of Maggie's young life is her encounter with a book of Thomas a Kempis's writings, which recommend abandoning one's cares for oneself and focusing instead on unearthly values and the suffering of others. Maggie encounters the book during the difficult year of her adolescence and her family's bankruptcy. Looking for a "key" with which to understand her unhappy lot, Maggie seizes upon Kempis's writings and begins leading a life of deprivation and penance. Yet even in this lifestyle, Maggie paradoxically practices her humility with natural passion and pride. It is not until she re- establishes a friendship with Philip Wakem, however, that Maggie can be persuaded to respect her own need for intellectual and sensuous experience and to see the folly of self-denial. Maggie's relationship with Philip shows both her deep compassion, as well as the self-centered gratification that comes with having someone who fully appreciates her compassion. As Maggie continues to meet Philip Wakem secretly, against her father's wishes, her internal struggle seems to shift. Maggie feels the conflict of the full intellectual life that Philip offers her and her "duty" to her father. It is Tom who reminds her of this "duty," and Maggie's wish to be approved of by Tom remains strong.
The final books of The Mill on the Floss feature Maggie at the age of nineteen. She seems older than her years and is described as newly sensuous—she is tall with full lips, a full torso and arms, and a "crown" of jet black hair. Maggie's unworldliness and lack of social pretension make her seem even more charming to St. Ogg's, as her worn clothing seems to compliment her beauty. Maggie has been often unhappy in her young adulthood. Having given up her early asceticism, she longs for a richness of life that is unavailable to her. When she meets Stephen Guest, Lucy Deane's handsome suitor, and enters into the society world of St. Ogg's, Maggie feels this wont for sensuousness fulfilled for the first time. Stephen plays into Maggie's romantic expectations of life and gratifies her pride. Maggie and Stephen's attraction seems to exist more in physical gestures than in witty discussion, and it seems to intoxicate them both. When faced with a decision between a life of passionate love with Stephen and her "duty" to her family and position, Maggie chooses the latter. Maggie has too much feeling for the memories of the past (and nostalgia for a time when Tom loved her) to relinquish them by running away.
As a child, Tom Tulliver enjoys the outdoors. He is more suited to practical knowledge than bookish education and sometimes prefers to settle disputes with physical intimidation, as does his father. Tom is quite close to Maggie as a child—he responds almost instinctively to her affection, and they are likened to two animals. Tom has a strong, self-righteous sense of "fairness" and "justice" which often figures into his decisions and relationships more than tenderness. As Tom grows older he exhibits the Dodson coolness of mind more than the Tulliver passionate rashness, though he is capable of studied cruelty, as when he upbraids Philip Wakem with reference to Philip's deformity . Repelled by his father's provincial, small-minded ways and the mess these ways caused the family, Tom joins the ranks of capitalist entrepreneurs who are swiftly rising in the world. Tom holds strict notions about gender—his biggest problem with Maggie is that she will not let him take care of her and make her decisions for her. Tom's character seems capable of love and kindness—he buys a puppy for Lucy Deane, and he often ends up reconciling with Maggie—but the difficult circumstances of his young life have led him into a bitter single- mindedness reminiscent of his father.
Like the other main characters of The Mill on the Floss, Mr. Tulliver is the victim of both his own character and the circumstances of his life. His personal pride and rashness causes his bankruptcy; yet there is a sense, especially in his illnesses, that Tulliver is also sheerly overwhelmed by the changing world around him. Tulliver is somewhat more intelligent than his wife—a point of pride and planning for him—yet he is still "puzzled" by the expanding economic world, as well as the complexities of language. The lifestyle to which Mr. Tulliver belongs—static, local, rural social networks and slow saving of money—is quickly giving way to a new class of venture capitalists, like Mr. Deane. Part of the tragedy of Tulliver's downfall is the tragedy of the loss of his way of life. Mr. Tulliver is one of the few models of unconditional love in the novel— his affection for Maggie and his sister, Mrs. Moss, are some of the few narrative bright spots of the first chapters. Yet Tulliver can also be stubborn and obsessively narrow-minded, and it is this that kills him when he cannot overcome his hatred of Wakem.
Philip Wakem is perhaps the most intelligent and perceptive character of The Mill on the Floss. He first appears as a relief to Maggie's young life—he is one of the few people to have an accurate sense of, and appreciation for, her intelligence, and Philip remains the only character who fully appreciates this side of Maggie. Philip himself is well read, cultured, and an accomplished sketcher. Philip's deformity—a hunched back he has had since birth—has made him somewhat melancholy and bitter. Like Maggie, he suffers from a lack of love in his life. His attraction to Maggie is, in part, a response to her seemingly bottomless capacity for love. Philip's gentleness, small stature, and sensitivity of feelings cause people to describe him as "womanly," and he is implicitly not considered as a passionate attachment for Maggie. It is Philip who urges Maggie to give up her unnatural self-denial. He recognizes her need for tranquility but assures her that this is not the way to reach it. Through the remainder of the novel, Philip seems to implicitly offer Maggie the tranquility that she seeks—we imagine that Maggie's life with Philip would be calm, happy, and intellectually fulfilling.