One of the key points of Gordon Clark’s Scripturalism is that we are just as dependent on God for knowledge as we are for salvation.
Those in the Reformed community, at least those who are actually Christians, will readily admit that salvation is by grace alone, through belief alone, in Christ alone.
But oddly, many of the same people are sound on the doctrine of salvation at the same time hold to a theory of knowledge (epistemology) that is at odds with their view of salvation.
It is not uncommon to hear some Christians talk as though there are two sources of knowledge, revelation in the 66 books of the Bible and sense experience (empiricism).
This admixture of revelation and sense experience in Christian thought can be traced back to Thomas Aquinas. John Robbins explains,
Thomas Aquinas, the great thirteenth-century Roman Catholic theologian, tried to combine two axioms in his system: the secular axiom of sense experience, which he obtained from Aristotle, and the Christian axiom of revelation, which he obtained from the Bible. His synthesis was unsuccessful. The subsequent career of western philosophy is the story of the collapse of Thomas’ unstable Aristotelian-Christian condominium (An Introduction to Gordon H. Clark)
One of the problems with Protestantism over the centuries is that it never produced a philosopher who challenged Aquinas’ theory of knowledge. As a result, Aquinas’ erroneous synthesis of “the secular axiom of sense experience…and the Christian axiom of revelation” was accepted by large segments of the Christian church.