This paper argues that the negativity of hermeneutic experience is revelatory for the following reasons. Hermeneutic failure is not the equivalent of making an erroneous step in a closed circuit of reasoning. Neither is it a refutation. It concerns becoming conscious of an omission, an oversight, an unjustifiable claim to completeness and even the displacement of one interpretation by another more suggestive. The negative dimension of hermeneutic failure is incontrovertibly connected with becoming progressively aware of how, contrary to expectations, a different way of seeing is possible: something comes to light which displaces one’s former judgement. Consciousness of failure is, then, indissociable from an emergent awareness of overlooked and unremarked ways of thinking: “I should have been alert to this” or “I failed to take account of that.” Consciousness of failure is revelatory precisely because something else and something other than my expectation has shown itself to be decisive and in so doing has displaced my former understanding. This is the basis of the claim that the educative and spiritual importance of hermeneutics lies precisely in the practical pursuit of the impossible. It is a key contention of the paper that hermeneutic understanding expands and extends itself as a consequence of its impossible quest for completion.