Fundamental v. non-fundamental doctrines

 Fundamental doctrines are those doctrines, belief in which is necessary to salvation. These beliefs in a rudimentary sense identify a person as a Christian. For many, the Apostles Creed is viewed as the substantive content of true faith (e.g., Heinrich Bullinger). John Calvin observed that not all doctrines are of the same sort. Some doctrines must be believed which, if they be denied, would undermine the Christological foundation of the truth of the gospel. These include the beliefs that God is one, Christ is God, Christ is the Son of God, and salvation is by grace. Other articles of faith, though disputed, do not break the unity of the faith (e.g., whether one must believe that at death human souls go to heaven, or simply that they live to the Lord) (Calvin Institutes 4.1.12). Subsequent to the Reformation, Lutherans saw belief concerning the mode of Christ’s presence in the Lord’s Supper to be a fundamental doctrine, whereas the Reformed did not.

In the history of Protestantism, the positive function of the distinction between fundamental and non-fundamental doctrines arose with the appearance of the catechisms of the Reformation. Usually such catechisms treated the Decalogue, the Apostles’ Creed, the Lord’s Prayer, and the sacraments. In order to produce a digest of biblical teaching, the church must employ some distinction like this. Reformed thinkers even distinguished between those articles of faith that are catholic or universal, which are to be believed and taught unto salvation, and thus taught in catechesis—and those articles which are theological, which are necessary for theological work but not for faith (such as extra-biblical historical and archaeological facts). Reformed churches have sought to steer a middle course between those who rejected any notion of basic doctrines altogether, and those who multiplied fundamental doctrines. In addition, some recognized a difference between the doctrinal rules and judgments of particular churches, and doctrines enjoying the general assent of the universal church.

            [1] For a thorough historical discussion of the rise and function of the distinction between fundamental and non-fundamental doctrines in the period following the Reformation, see Richard Muller in Prolegomena to Theology, 2nd ed., Post-Reformation Reformed Dogmatics: The Rise and Development of Reformed Orthodoxy Ca. 1520 to Ca. 1725, vol. 1 (Grand Rapids: Baker, 2003), esp. pp. 406-430.