Certainty and Security in Martin Luther’s Theology
Authors: Schreiner Susan E. 
Published: March 2017

Crucial for Luther’s theology and his own experience was the question of whether one’s salvation was certain. And the security of the truth which underlay doctrine was complexly related to that question. Luther thus received and developed notions of certitude and security. The concepts as Luther inherited them have a long and somewhat complicated history that can be traced back to ancient Greece. These terms were often distinct throughout antiquity and up to contemporary times. The term “security” has referred to the realm of the political; namely, the security or tranquility of the city state or “nation” both in terms of physical security in times of conflict and also in the history of law. Certitude has a more complex history. For example, Aristotle often understood certainty or akribeia to mean precision, especially in mathematical terms. Those sciences that had the most properties removed (aphaeresis) were the most precise and consequently the most certain. Most prominent in the history of certitudo was the issue of epistemic certainty. Thus we find in Augustine’s doctrine of illumination that uncreated, immutable exemplars were the guarantors of certainty. It was in the later Middle Ages that the issue of epistemic certainty, in the form of mental representation, became a controversial topic. Scotus criticized Henry of Ghent’s views of human cognition and contended that certainty could be had only of self-evident propositions, knowledge of contingent acts, repeated occurrences ordained by God, and sense knowledge of the external world. Ockham argued for epistemic certainty on the basis of self-evident propositions and, most importantly, the reliability of intuitive cognition of individual external objects.

Certainty also had a long history in Christian theology and most often referred to the certainty of faith. Certitude was the conviction of the truth regarding the contents of the faith. Frequently the issue referred to the relationship between faith and reason. Certainty referred primarily to definition of the Christian faith. Not surprisingly, throughout the Christian tradition, certainty was related to the problem of heresy. The early church Fathers tried to establish orthodox doctrine over and against various heretical groups. Everyone agreed that the foundation for Christian truth was Scripture. However, different people interpreted the Bible in ways that were judged to be contrary to Christian faith. Around the year 434, Vincent of Lérins provided a rule that distinguished Catholic truth from heresy. This “Vincentian Canon” required that Christian truth be that which was believed everywhere, always, and by all (Quod ubique, quod semper, quod ab omnibus). These criteria guaranteed the certainty and stability of doctrine. One target of Vincent’s was probably Augustine, because he could be quoted against himself. Due to the many conversions in his life, Augustine made many pronouncements he later retracted, and such retractions were not meant to contribute to uncertainty about the faith. Medieval Scholastic inheritors of Augustine continued to define faith as a cognitive certitude. Their training in dialectic was crucial because it provided the certainty of doctrine against heretics. Luther was trained in dialectic, but in his Disputation against Scholastic Philosophy he opposed the use of Aristotle and logic in theology. Nonetheless, dialectic remained a subject in the university at Wittenberg.

Dialectic could not answer the questions of certainty for which Luther sought answers. His questions were about the certainty of salvation and, for Luther, this certainty could only be found in Scripture and the experience of the Holy Spirit. Such certainty also required a redefinition of faith. As the various reformations continued to divide Western Christendom, controversies about the exegesis of Scripture multiplied both among various reformers and between reformers and Catholics. Throughout the course of the turbulent 16th century, the real source of certainty for all parties became the Holy Spirit.

Throughout the late Middle Ages, certainty and security referred to the relationship between the individual and God. For Martin Luther and the other Protestant reformers, these terms took on a meaning beyond the faithful knowledge of the contents of the faith. Any examination of Luther’s writings show that he used “security” and “certainty” synonymously to refer to the certitude of salvation whereby one experienced the security, assurance, and certitude of God’s benevolent will. Moreover, despite his lack of a firm terminology, Luther meant the same thing by “the certainty of forgiveness,” “the certainty of justification,” and “the certainty of God’s good will,” as well as the phrase, “the certainty of being in a state of grace.” All of these phrases referred to the certainty of salvation or the security of knowing that God’s benevolence was directed to one’s own individual salvation.