In the 21st century, philosophy of biology and studies in sexuality are dominated by the contrasting views of idealist deconstructionism and materialist naturalism. Not unlike the nominalists and scholastic realists of Martin Luther’s day, contemporary philosophers, scientists, theologians, and sociologists debate whether human constructs form all that is known or if the material world gives rise to truths about bodies, desire, and sexuality. In the context of the medieval debate, Luther rejected philosophy as an adequate discipline in the most important discussions concerning human nature. He turned away from speculative philosophy to focus on evangelism of the Gospel. The heart of Luther’s reformation was his insistence on the truth of the Incarnation and the justifying grace of God given through Christ’s death and resurrection. Luther’s evangelical proclamation, rooted in the Gospels, the letters of Paul, and in the early fathers of the church, especially Augustine, reoriented many issues of the medieval church, including views concerning the body, desire, and sexuality.
Luther’s understanding of the Incarnation had specific ramifications for his views concerning the body, sensuality, desire, and sexuality. From Luther’s reading of scripture and his pastoral and familial work in the world, he came to expound that humans are bodily creatures with physical needs, driven to provide for these needs by desire. Human need for relationship is also driven by desire. As Christ befriended, healed, fed, and washed the bodies of those he met, so too the Christian is called to human relationship with others and the bodily service of the neighbor. This is also true in romantic relationship, which has a bodily element for Luther, who rejected sexual abstinence as a human virtue.
Luther’s understanding of justification is critically important to this discussion. Luther knew that sin wreaks havoc in all human relationship, including loving sexual relationships. Because sin, for Luther, is centrally a problem of unbelief, a problem that manifests in false pride or despair, the solution to sin is not the law but faith in God’s redeeming grace. What justifies desire and sexuality is not obedience to the law but faith, which allows God’s love to flow from the lover to the beloved. While a civic use of the law can aid lovers who seek to know how best to care for each other, it is by faith that the lovers’ desire is justified. Indeed, through faith, the lover’s desire for the beloved becomes utterly for the beloved’s sake, a desire that teaches the lover about the absolute love of Christ. In this way, marriage, including the mutual sexual desire of the spouses, is a schoolhouse of faith, which while ever sinful is also justified.
Luther has no doctrine or treatise specifically on bodily desire and sexuality. An attempt to create such a doctrine would be wrongheaded. However, Luther’s theological claims concerning the Incarnation and God’s justifying grace through Christ reframed the discussion of these issues in his day. Contemporary discussion and debate about sexuality would profit from a careful examination of Luther’s re-formation of the discussion of these issues.