We learn about the idea of formal and material principles from F.E. Mayer’s book, The Religious Bodies of America. In this book he shares that a church’s formal principle is the authoritative source of their theology. Authoritative sources can range from the Bible, to Church tradition, to personal experiences, to pragmatism, to local folk theology, to popular opinions, and so forth. Furthermore, it is from the authoritative source that the central teaching typically emerges. This central teaching can be considered the church’s material principle. Central teachings (i.e., material principle) can range from the doctrine of Justification, to social activism, to perfect sanctification, to creationism, to pious living, and so forth. In other words, a formal principle tends to be certain texts or respected leaders of a particular church/movement, whereas the material principle is the church/movement’s central teaching; the central focus and emphasis, if you will.
Both formal and material principles are important for they help one understand a church’s authoritative source of theology from the theology itself. In other words, a church’s formal principle is the authoritative source; however, one cannot dismiss the church’s material principle as irrelevant and powerless. The reason being, the material principle often provides rules for dealing with and handling the authoritative source. For instances, two different church denominations can hold to the Word of God as the quintessential knowledge source (i.e., formal principle), however, different epistemic assumptions and different worldviews can emerge due to a variance in the denominations’ material principles.
A great example of the importance and power of both formal and material principle can be found in the emergence of seventeenth-century Lutheran Pietism. To my understanding, the Father of Pietism, Philip Jacob Spener, never publicly dismissed the teachings of Luther and the teachings of the Reformation; Spener never rejected the Lutheran formal principle. However, there is substantial evidence that the movement, which was birthed by Spener, shifted and deviated from the Lutheran formal ‘and’ material principles. “Pietism made religious experience more important than Christian doctrine and stressed sanctification more than justification.” By including ‘experience’ as an additional authoritative source and stressing ‘sanctification’ more than justification, both the formal and material principles of Pietism resulted in not merely shifting the priorities of the church, but brought about an entirely new theological position for Christendom.
Keep in mind that formal and material principles are indeed extremely powerful. Additions, subtractions, reductions, and emphasis shifts to the formal and material principles of the church result in dramatic consequences; consequences such as unique epistemic assumptions, variant worldviews, confused linguistics, and heterodox practices. In other words, alterations to a church’s material principle may result in seismic changes; alteration such as: changes in emphasis, changes in the frequency of mentioning a doctrine, changes in what doctrine dominates, and so forth. Looking back at the seventeenth-century historic example that was used earlier,
“When Pietism shifted the emphasis from the law as mirror (to show us our sins) to the third use of the law (as a rule or guide), legalism resulted. For the pietists the main purpose of the law was to give a set of legal requirements for Christian living. They tried to use the law to motivate Christian living. This is an improper use of the law and a characteristic of Reformed rather than Lutheran theology.”
Please note that Pietism did not deny the second use of the Law, but shifted away from the foremost office and power of the Law (i.e., the foremost office and power of the Law is to reveal inherited sin and its fruits). This emphasis shift, which may seem insignificant, mistakably led to the failure of many individuals not recognizing the total depravity of human nature, as well as a loss in understanding that the Christian is simultaneously a saint and sinner. Thus, many of these Pietists “therefore had an unrealistic optimism for sanctification that bordered on perfectionism.”
In summary, both formal and material principles function as sources of knowledge; they are indeed, very significant. Additions, subtractions, reductions, changes in the frequency of use, and yes, emphasis changes, are of great importance in regard to one’s formal principle, but equally are just as important to one’s material principle, if not more.
Things to Consider:
What is your authoritative source of your theology? Where do you derive your theology from?
• Self; What Feels Right
• Past Experiences
• The Bible
• Traditions of the Church
• Pragmatism; whatever works
• Popular Opinion
• Republican/Democrat Talking Points About God
• Preacher (i.e. local or TV)
• Local Cultural Norms
• Historic Christian Leader
Once you have assessed the question above, consider the following.
What is your central doctrine and/or focus?
• End Times
• Victorious Living
• Christ Crucified
• Social Activism
• Gifts of the Spirit
• God’s 10 Commandments
• God’s Sovereignty
• Pious Living
• God’s Love
• Perfect Sanctification
 F.E. Mayer, The Religious Bodies of America, fourth edition, (Saint Louis, MO: Concordia Publishing House, 1961), passim.
 John M. Brennar in the Forward of Valentin Ernst Loescher’s book The Complete Timotheus Verinus (Milwaukee, WI: Northwestern Publishing, 2006) , v.
 Bengt Hagglund, History of Theology (Saint Louis, MO: Concordia Publishing House, 1968), 325.
 John Brenner, Pietism: Past and Present (Essay delivered at WELS Michigan District Southeastern Pastor/Teacher/Delegate Conference on January 23, 1989 and WELS Michigan District Northern Pastoral Conference on April 3, 1989), 5.
 Martin Luther, The Smalcald Articles: Book of Concord (Saint Louis, MO: Concordia Publishing House, 2000), 312.
 Brenner, Pietism: Past and Present, 5.