The article argues, firstly, that in view of the relationship between Protestantism and the English Enlightenment it is in distinctively non-Protestant religious thought, within or without the Church of England, that the central themes of the English Counter Enlightenment are to be sought. The writings of the Nonjurors can and should therefore be seen as possessing a wider significance than that derived from the history of theology. They constitute an important part of the Enlightenment/ Counter Enlightenment debates, and this flows naturally from the position they occupy in relation to the Catholic and Reformation traditions. The study exemplifies this view with reference to the writers of the Usager movement. There is, in the second part, a statement of the fundamental theological causes of the Usager schism. The third part displays the significance of these concerns to the Enlightenment/ Counter Enlightenment debates and in particular to the central matter of these debates - the epistemological and institutional location of authority.