We must therefore give our opponents better treatment than they give us. We must point out to them that univocal reasoning itself leads to self-contradiction, not only from a theistic point of view, but from a non-theistic point of view as well. It is this that we ought to mean when we say that we must meet our enemy on their own ground. It is this that we ought to mean when we say that we reason from the impossibility of the contrary. The contrary is impossible only if it is self-contradictory when operating on the basis of its own assumptions.
– Cornelius Van Til, A Survey of Christian Epistemology p.205