In the first half of the 19th century, the rapid development of science in its modern form reinforced the belief that the existence of God could be proved. "Natural theology, " as it was then called, was the theoretical framework in which Emily Dickinson was taught science at Amherst College. This article traces the influence of Dickinson's scientific schooling on her poetic use of the concept of "circumference. " By calling into question the dogmatic character of both religion and science through a subversive use of this mathematical notion, Dickinson opposes all forms of centrality and exposes her own, more open conception of the world, which relies on negation and the fluidity of signs. "Circumference" can be viewed as a structuring image of Dickinson's mental universe and it gives shape to her unfinished body of poems.