The other day I was reading a chapter for a friend, and he mentioned the material and formal principles of the Reformation. My editorial suggestion was that he define the terms, since not everyone knows what they mean.

Later I realized that I had never stopped to ask who came up with this terminology. I know the concepts go back to Aristotle, but when did they begin to be applied to the heart of the Protestant Reformation?

So here’s a quick overview.

What Is the “Material Principle” of the Reformation?

The material principle of the Reformation is justification by grace alone (sola gratia) through faith alone (sola fide).

It’s hard to improve upon the Westminster Longer Catechism’s definition: for elect believers, God “pardons all their sins, accepts and accounts their persons righteous in his sight; not for any thing wrought in them, or done by them, but only for the perfect obedience and full satisfaction of Christ, by God imputed to them, and received by faith alone” (WLC 70).

What Is the “Formal Principle” of the Reformation?

The formal principle of the Reformation is Scripture alone (sola Scriptura).

In other words: “Scripture is to be understood as the sole source of divine revelation, the only inspired, infallible, final, and authoritative norm of faith and practice.”

Who Came Up with This Language?

The terms have been traced back to the German Lutheran theologian August Twesten (1789–1876), a former student of Frederich Schleirmacher who became his successor at the University of Berlin. He described the principles of the Reformation this way in Vorlesungen über die Dogmatik der evangelisch-lutherischen Kirche (Hamburg: Perthes, 1826).

The terminology came into the common academic lexicon a generation later when used by Albrecht Ritschl in Die christliche Lehre von der Rechtfertigung und Versöhnung (Bonn: A. Marcus, 1870).

What Does All of This Have to Do with Aristotle?

The terms material and formal can be a bit confusing, even misleading, in English, because we tend to think that the opposite of formal is informal, and the opposite of material is immaterial.

We need to go back to the Greek philosopher, Aristotle (384–322 BC), the student of Plato and the tutor of Alexander the Great. (In terms of the biblical timeline, Aristotle lived during the intertestamental period, the years of silence between the Old and New Testaments.)

If philosophy “consists of a series of footnotes to Plato” (A.N. Whitehead), then Aristotle is “the primary footnote to Plato” (Peter Kreeft).

If you asked Aristotle why something is the way that it is, he would point out that we can mean four different things when we ask for the cause or reason or explanation (Greek: αἰτία) of a substance.

In other words, “because” can be answered in four different ways because there are four different ways to explain it.

Let’s take a table as an example. If someone says, “What makes a table?” they could be asking four different types of things:

  1. What is a table made out of?
  2. What is the form or essence or pattern makes something a table?
  3. What produces or leads to a table?
  4. What is a table for?

And we might answer:

  1. A table is made out of wood.
  2. A table is made by having four legs support a flat surface.
  3. A table is made by a carpenter.
  4. A table is made for eating.

Though Aristotle didn’t use the following terminology, he did use these concepts:

  1. The material cause is “that out of which” something is made.
  2. The formal cause is the pattern or form of the object, that which comes together to make it into a particular thing.
  3. The efficient cause is what led to it becoming what it is.
  4. The final cause is the end/goal of the object, or what the object is good for.

Allison Spiegel offers this illustration:

Back to the Reformation

So now we can go back to the Reformation.

The material cause of the Reformation—that doctrine out of which the Reformation was made—is the doctrine of justification by grace alone through faith alone. As Luther said, “if this article [of justification] stands, the church stands; if this article collapses, the church collapses” (WA 40/3.352.3).

The formal cause of the Reformation—the form or pattern or structure or direction that determined the Reformation—is the doctrine of Scripture alone as our final authority in faith and practice. Without Scripture, we would not know that justification is precious and true.

So the next time you hear these terms, you may not remember the name of Twesten, or may not remember how to parse the Aristotelian Four Causes, but do remember that Scripture forms the doctrine, or the material, of the movement that sought to reform the church, returning her to biblical roots, for the glory of God alone.