 However, having marked out a hierarchy between philosophy and theology in this manner, Luther does not entirely reject a role for reason within theology, when properly understood, and when thereby illuminated by faith so that it becomes “right reason” (recta  ratio).[18]  Thus, as Gerrish has argued in relation to Luther’s famous statement when asked to recant at the Diet of Worms, that he refused to do so unless “convinced by the testimony of Scripture or plain reason”, Luther did not mean here to set up reason alongside scripture, but rather to accept the evidential authority of rational inferences from it (Gerrish 1962:  24–5).[19]  Likewise, while his doctrine of putting scripture first as the basis for faith (sola scriptura) means he has a correspondingly dim view of theological debates carried out at a purely philosophical level, Luther nonetheless accepts the importance of reason to the interpreter and translator of the scriptural texts such as himself. Indeed, part of his grounds for rejecting Erasmus’s humanistic appeal to authority and tradition in matters of interpretation lies in Luther’s confidence in the capacity of reason to make the Bible clear, when properly coupled with faith and the “understanding of the heart” (see Grosshans 2017: 15–17). However, Luther was himself to face the challenge of those (such as the Anabaptists and the Sacramentarians at the Colloquy of Marburg in 1529) who interpreted scripture in different ways, and for whom conscience guided by “right reason” was to counsel different responses to such key passages as “For this is my body”, leaving little agreed common ground on which to adjudicate these disputes; some see this situation as ironically generating a kind of scepticism which is the very converse of the certainty which Luther himself craved and claimed to make  possible.[20]