What happens when thinking no longer secures a rational foundation for knowledge and acting no longer means conforming one's daily enterprises public and private to that foundation? In his brilliant deconstructionist analysis Reiner Schurmann provides a comprehensive interpretation of Heidegger's thinking from the perspective of this question. Focusing on the relationship between theory and practice in era in which metaphysical rationally has come to an end Schurmann explicates an economy of presencing in which thinking can no longer be called upon to legitimize praxis by measuring it against some enduring principle of arche. Thinking and acting he concludes can then become an-archic.