The scholastics, both Protestants and Catholics, picked up Aristotle’s Four-fold causation, though the Protestants would make one key adaptation. The example being used is that of wood and a tree.
- Material cause: matter itself is a cause of change. The wood itself is involved in the cause.
- formal cause: The table is “imprinted” on the wood, so that the form is a cause of change of the matter.
- Final Cause: The goal of the wood. Potency thus becomes actuality (The Reformed would qualify this, though, for we note that not all potencies are actualized. )
- The efficient cause: the furniture maker.
The Reformed would add one more category: the instrumental cause. Van Asselt describes this as a subordinate efficient cause (40). God is the efficient cause of all that takes place in reality, and in particular The Holy Scriptures (cf. Muller, PRRD II). Yet humans are not merely passive in salvation (thus rebutting the monothelite charge), and thus human action is the causa instrumentalis of salvation. This distinction is of utmost importance. If humans were the efficient cause, then they are causing their own salvation; thus the Reformed do not go beyond the causa instrumentalis.
This is seen in debates over Paul/James and Faith Alone. I will say more of this when I deal with Maccovius’ use of categoremata and syncategoremata. Suffice to say, if someone asks the Reformed Scholastic, “Do you believe in faith alone, contra James 2?” the answer is, “It depends on how the terms are being used.” Do I believe in works-salvation? If one is referring to final causality, then yes! Ephesians 2:10 says we are created for (final cause) good works. If one is referring to causa instrumentalis, then the answer is no.