This is a list of Gordon Clark quotes about presuppositions and axioms.
The books from which these quotes came are published by the Trinity Foundation. You can purchase the books at these links:
Table of Contents
Axioms Cannot Be Deduced, But Are Tested Another Way
But that revelation should be accepted without proofs or reasons, undeduced from something admittedly true, seems odd when first proposed. It will not seem so odd, however, when the nature of axioms is kept in mind. Axioms, whatever they may be and in whatever subject they are used, are never deduced from more original principles. They are always tested in another way.
If a philosopher ponders the basic principles of Aristotle, Kant, or even Sartre, he will do so by considering how well the author succeeds in solving his problems. If the problems are such as confront us all, and if the basic proposals succeed fairly well, a philosopher is inclined to give his assent to them. He cannot by strict logic be compelled to assent; he makes a voluntary choice, induced by the successful solution of the problem. So too it should be with Christian revelation as an axiom. We must ask, Does revelation make knowledge possible? Does revelation establish values and ethical norms? Does revelation give a theory of politics? And are all these results consistent with one another? We can judge the acceptability of an axiom only by its success in producing a system. Axioms, because they are axioms, cannot be deduced from or proved by previous theorems.
Gordon H. Clark. “Clark and His Critics.” Apple Books. 118-119.