Thomas Aquinas: Summa Theologiae 1266–1273

The magnum opus of the medieval Christian philosopher and theologian Thomas Aquinas, the Summa theologiae(also known as Summa theologica, “Summary of Theology”) is a massive work that aims to expound all of Christian theology as systematically as possible. It is written in Latin, the universal language of medieval European scholarship and law. At its broadest level, the Summadepicts in philosophical terms the relationship between God and humanity and delineates how human reconciliation with God is made possible through Christ. Spanning three volumes treating God, humanity, and Christ the Redeemer, the Summais arranged as 518 questions divided into 2,652 articles. Each article states the negative and positive sides of the proposition under examination, the arguments pro and con, and then Aquinas’s solution. The first and most famous volume (from which our excerpts are drawn) deals with the theological enterprise as well as the existence and nature of God. The second volume deals with humanity, examining the purpose of life, the cardinal and theological virtues, venial and mortal sins, and kinds of law. The third volume deals with Christ vis-à-vis his Incarnation, the sacraments he explicitly or implicitly instituted, and his Resurrection. The Summais arguably the preeminent construction of Scholasticism, a theological method that was practiced among the three Abrahamic religions (Judaism, Christianity, and Islam) from the eleventh to the fourteenth centuries and that attempted to reconcile faith and reason. Accordingly, the Summaargues both for the rationality of the Christian faith and for the validity of employing philosophy in the service of theology. Philosophy can be used to show the error of unbelievers and to enrich and deepen the faith of believers. By harmonizing the life of the spirit with the life of the mind, Aquinas endeavored to furnish a genuinely rational and universal view of all existence.