This article attempts to show that the performance of personal and communal Christian faith bears an intrinsic criterion by means of which its quality is to be assessed. This criterion is orthodoxy. In order to substantiate the thesis, a thought experiment will be conducted. In the first part, the experiment demonstrates as to why a purely private interpretation of faith is almost unbearable so that private faith seeks to expose itself to an external examination. Such exposure, as will further be argued, necessarily entails the introduction of a binary code, namely true vs. false or orthodox vs. heterodox. Continuing the thought experiment in the second part, the primary mode of the external examination will be presented as a communal practice of faith. In case this practice is disturbed, however, the examination mode changes from cooperation into a reasonable discourse about orthodoxy. Finally, it will be shown that the quest for orthodoxy cannot be restricted to the faith community alone but reaches beyond it and eventually proves to have a universal scope.