In Reformed Dogmatics, Bavinck contends for the use of the word principium for Scripture rather than the use of fons, as the latter mistakenly pictures Scripture as a well from which to draw doctrine mechanically, which the editor claims to be Charles Hodge’s view (this is the abridged one-volume version.) Principium, on the other hand, “suggests an organic connection.” He then claims that Scripture contains material for dogma, but formally, there is no dogma in it. What does he mean by this? What’s wrong with Hodge’s method? I’m struggling to see the point in his distinction between the two.
In chapter 2 of his
Principles of Sacred Theology, Abraham Kuyper addresses this distinction directly. The intent is to distinguish Holy Scripture (the revelation therein) from all other sciences. All other sciences are obliged to employ, as Kuyper explains, a common principium of knowing. Kuyper states, "Since, on the other hand, the object of theology excluded every idea of coördination, and thinking man, who asked after the knowledge of God, stood in a radically different relation to that God than to the several kingdoms of created things, there
had to be a difference in the principium of knowing.
With every other object it was the thinking subject that took knowledge; here it was the object itself that gave knowledge." (the bold print is my own emphasis).
My "take-away" from this is that Scripture is not simply a well of knowledge from which we draw and construct our theology, but Holy Scripture is God Himself speaking, disclosing Himself, thus
GIVING us the knowledge of Himself. This distinguishes theology from all other sciences, which is why Scripture should be regarded as the
principium unicum (sole or only principle) for theology. Only God can reveal God, and I think that's the point being emphasized by Bavinck's distinction.
As Reformed Christians, we readily acknowledge the spirituality of the word of God in regeneration, i.e. God is pleased through the ministry of His word by the power of His Spirit to impart spiritual life to His elect people, thereby granting us faith to embrace the Lord Jesus Christ. I love how, when pressed to describe how faith originates, Basil of Caesarea emphasized that it comes by the operation (or "energy" as the eastern writers put it) of the Spirit.
Basil of Caesarea (Ad 329-379): Faith, which draws the soul unto consent above the efficacy of all ways or methods of persuasion; faith, that is wrought and begotten in us, not by geometrical enforcements or demonstrations, but by the effectual operations of the Spirit. The Works of John Owen, A Vindication of the Animadversions on “Fiat Lux,”Vol. IX, ed. William H. Goold, (Edinburgh: The Banner of Truth Trust, Third printing, 1977), vol. XIV, p. 84.
Greek text: Πίστις, ἡ ὑπὲρ τὰς λογικὰς μεθόδους τὴν ψυχὴν εἰς συγ κατάθεσιν ἕλκουσα· πίστις, οὐχ ἡ γεωμετρικαῖς ἀνάγκαις, ἀλλʼ ἡ ταῖς τοῦ Πνεύματος ἐνεργείαις ἐγγινομένη. In Psalmum CXV Homilia, PG 30:104B.
Hence God Himself is our
principium cognoscendi (principle of knowing), inasmuch as it is God who
grants us the knowledge of Himself through His God-breathed word, the holy scriptures. Hence this distinction places Scripture in the category of a first principle rather than simply as a source (well,
fons) of knowledge about God.
I recommend the purchase of Richard Muller's
Dictionary of Latin and Greek Theological Terms. It's one of those great reference books to which one returns again and again. He reminds us that "according to the Protestant scholastics, theology has two
principia, Scripture and God, i.e., the revelation and the one who reveals himself." p. 245.