"For-mal Prin-ci-ple": the authority from which a system of thought is shaped or formed.
In a brief but helpful article, Ian Hamilton reclarifies Calvinism's formal principle:
B.B. Warfield, the great Princeton theologian, said that the fountainhead of Calvinism does not lie in its theological system, but in its 'religious consciousness'. What he meant is that the roots of Calvinism are planted in a specific 'religious consciousness,' out of which unfolds (as day follows night) a particular theology... This is what so many miss in their assessment of, or espousal of, Calvinism. It is not first and foremost a theological system; it is more fundamentally a "religious attitude", an attitude that gives inevitable birth to a particular, precise, but gloriously God-centered and heart-engaging system of theology.It is sometimes suggested that we who adhere to the Calvinist system do so because we are either “stuffy” (i.e., a pedantic concern for coherence in theological minutia) or “irrelevant” (i.e., an anachronistic affinity for antiquated authors and writings). True Calvinism, however, does not begin with such personal predilections.
- Ian Hamilton, "Heart-Warming Calvinism" (HT: Ligonier Ministries).
True Calvinism grows from embracing and from marveling at the work of God and the God who works with child-like awe. Our system is rooted in an unprejudiced and an unconditional worship of whom God reveals Himself to be because He is so strikingly glorious.
This is Warfield’s “religious consciousness,” and even more, Paul’s exuberant doxology, “Oh, the depth!” Calvinism simply flows from an intoxicating glance at the glory of God. He is our formal principle.
(We may spend more time with Hamilton's article this week as he explains “experimental Calvinism”).