The book examines the role of education in the lives of the characters and how such education and study has affected the characters. Rosamond Vincy's finishing school education is a foil to Dorothea Brooke's religiously-motivated quest for knowledge. Rosamond initially admires Lydgate for his exotic education, and his intellect. A similar dynamic is present in Dorothea and Casaubon's relationship, with Dorothea revering her new husband's intellect and eloquence. In both cases, however, the young wives' expectations of their husbands intellects are not reflected in reality.
Despite extreme erudition, Mr. Casaubon is afraid to publish because he believes that he must write a work that is utterly above criticism. In contrast, Lydgate at times arrogantly flaunts his knowledge, making enemies with his fellow physicians. He regards the residents of Middlemarch with a certain amount of contempt stemming from his belief that the townspeople are backwards and uninteresting. However, his education has not included tact and politicking, skills necessary in a small town but are seen by Lydgate as below him, the brilliant doctor. (summary from Wikipedia)