"The Gospel of salvation can only be believed in; it is a matter of faith only. It demands choice. This is its seriousness. To him that is not sufficiently mature to accept a contradiction and to rest in it, it becomes a scandal -- to him that is unable to escape the necessity of contradiction, it becomes a matter for faith.... He who finally makes open confession of the contradiction and determines to base his life upon it -- he it is that believes."
-- Karl Barth, Epistle to the Romans, 1933
Critique:
"Here is unalloyed fideism, fideism in its pure state. Faith is a decision -- it requires resting in contradiction. Faith is more a matter of will (choice) than of mind. This is the leap-of-faith syndrome which refuses to ground faith in any rational proof or evidence. Not only is rational evidence unnecessary to the fideist, it is undesirable as well, signaling a kind of intrusion of pagan categories of thought into the pristine purity of faith."
R.C. Sproul, J. Gerstner, A. Lindsley, Classical Apologetics: a Rational Defense of the Christian Faith and a Critique of Presuppositional Apologetics, Academie Books, Zondervan (1984).
If knowledge of God cannot be attained through a reasoning process, like a proof in geometry, then how is it attained? The fideist claims that it is in fact impossible to attain rationally, but must be apprehended by a totally nonrational leap of faith. This is the claim of fideism. It is an exaggeration of pessimism regarding the knowledge of God.