Historical scholarship has traditionally focused on the commonalities uniting Catharine Beecher and Mary Lyon, the two leading antebellum women's educational reformers in New England. This essay shifts that focus by contrasting their educational philosophies and exploring the implications their differences had for the development of American women's collegiate education. Despite Beecher and Lyon's similar religious and educational backgrounds, a combination of childhood socio-economic differences and adult theological differences underlay disparities regarding which class of women each sought to educate, what social roles Beecher and Lyon thought these women should be educated to play, and what curriculum each believed would best accomplish their purposes. By contrasting the educational philosophies of Beecher and Lyon, the author shows that the Seven Sisters' decision to copy the liberal arts curriculum of elite male colleges was not a forgone conclusion, and neither was their high price tag. Their curriculum and the student population they targeted resulted from the ferment of ideas about gender, theology, and class generated by debates between Lyon, Beecher, and other female educational reformers in the middle of the nineteenth century. The author explores the formation of these ideas in order to clarify the ideological choices made in the design of American women's colleges--and their long-range implications. (Contains 45 footnotes.)