Abstract
This article analyzes the crisis of reality which concerns the ontology in the shestovian irrationalism as it is assumed by Benjamin Fondane in his philosophical essays and in his existential poetics. From a crisis of reality which is suffered by the poetry in the margins of the vanguards, Fondane is to think not only the philosophy of the tragedy in La Conscience malheureuse as an analysis at the bosom of the derrealization provoked by the rationalism, but as well to develop a poetics of an ontological reversal in relation to a poetry of the disaster, under antiplatonic principles, which offer an exit for the religious irrationalism, bringing out an «existential» poetry conceived as act and substantiation