At the turn of the twentieth century, after the American Civil War but before the World Wars, William James and others drew on the wisdom of the World’s religious traditions, especially the “mystical languages of unsaying,” to construct the modern category of mysticism in part to provide a common core around which divided peoples might rally in the hopes of forming a more perfect union both religiously and politically. Over one hundred years later, postmodern theorists turn to unknowingness at the heart of our most cherished knowledge of ourselves and our world as a resource rather than a threat to aid in our efforts to honor others. My dissertation examines such recent appropriations of ancient unsaying, but moves beyond the merely linguistic and logical to analyze the embodied and emplaced through comparing what I call mystical and mundane modes of undoing, such as Jamesian pragmatic participation in a pluralistic universe (Chapter 1); orthodox and heterodox, Eastern and Western embodiments of cosmic vibrations from ancient gnosis, through Christian mystical theology, to Allen Ginsberg’s poetry (Chapter 2); the yearning for more life meaning in African American religiosity represented by Howard Thurman, Langston Hughes, and Sojourner Truth (Chapter 3); and democratic theorizing from feminists to posthumanists (Chapter 4). With creative collisions of apparently disparate thinkers who nevertheless share similar dynamics of embracing “spiritual but not religious” practices, I seek to move discussions of the mystical forward through developing resources for understanding and transforming dynamics of oppression such as gender, race, class, species, and other issues of embodied difference. Using Jacques Derrida as a bridge figure, I counter what I call the linguistic misread of deconstruction to advocate for more aware participation in an embodied mode of experiencing a generative vulnerability that is absolutely universal. Understood anew, embodied finitude may provide resources for promoting justice by uniting around a different kind of common core—a common core of no common core. Indeterminateness, then, may mean daring to unknow ourselves and our others through participation in a mystery beyond clear cut divisions—immanent and transcendent, material and immaterial, male and female, human and animal.