Wittgenstein's explorations into the social functions of certainty show that we live within a network of unquestioned rules. Trauma disrupts these unquestioned certainties, substitutes new, authoritative convictions, and exiles the traumatized person from his or her previously shared world. Wittgenstein helps us see how the repetitive communications so familiar in traumatic reactions are attempts to overcome this exile by seeking a resonant understanding in the listener. When the exiling truths of trauma are acknowledged by another, a community of understanding is reestablished; some prior certainties may be regathered, and healing can occur. The disruption and restitution of certainties play a central role in certain forms of religious conversion and in rites of passage. These examples illustrate the importance of certainty as an organizing aspect of human experience.