Locke’s skeptical semiotics suggested that language could never grasp reality, but Reidian Common Sense philosophers insisted we could know the world directly and intuitively. Dickinson’s poems engage Common Sense theories which seem to discount the role of language in forming our perceptions. In her poetry, she works through and plays with Common Sense ideas about language, perception, and knowing, testing them against skeptical associationist ideas she found congenial to her work as a poet. In fact, Dickinson’s Upham textbook struggles to fend off the skeptical consequences of Brown’s Humean associationism as it undoes the Reidian realism in the perceptual process. In the course of reading several poems, I show that Dickinson’s poems work out the idea that language presents to us the only world we can know. Dickinson’s epistemological thinking works out a poetics content with “terms” and uncertainty, since the mediations of language produce and nurture human community.