Extended excerpt from Van Til's Apologetic: Readings and Analysis by Greg Bahnsen:
Apologetical disputes
between believers and unbelievers depend upon, include by reference, and arise
out of conflicting epistemologies. Conflicts over the theory of knowledge in
turn incorporate, function within, and must address differing world-and-life views
(with divergent concepts of man as a knower), if they would be resolved. The
bold defense of the faith offered by Van Til’s presuppositionalism is that the
unbeliever’s worldview fails to provide an adequate or workable theory of
knowledge in terms of which the non-Christian can intellectually challenge the
truth of Christianity. His presuppositions preclude the unbeliever from making
claims to know anything intelligible or meaningful.
The
Christian worldview begins with the personal, self-sufficient, sovereign, and
triune God, who created all things from nothing and made man to be His image.
God knows all things, and directs all events by His wise, providential plan.
Thus, all objects, properties, minds, events, general laws, and moral
prescriptions are determined, controlled, and related to each other by the mind
of the Lord. Whatever the Lord says is utterly truthful and unfailing in its
purposes, and that includes every passage of the Old and New Testaments. Human
behavior and reasoning have become immoral and futile, due to self-centered
rebellion against God. Man is biased against and hostile to the Lord and His
revelation, wishing to be his own ultimate authority (autonomous). He needs the
redemptive work of God’s incarnate Son (as a prophet, priest, and king) and the
regenerating work of God’s Holy Spirit to be saved from intellectual
foolishness, moral guilt, and eternal damnation. Given this overall “picture”
of God, the world, man, value, history, and salvation—the basic biblical world-and-life
view—the Christian can give an account of the objectivity of truth; the mind’s
correspondence to objects and other minds; the possibility of knowledge; the
rational and empirical procedures by which we learn, test, and justify
propositions; the possibility of our finite minds knowing universal, absolute,
and prescriptive concepts and laws; the human tendency toward disagreement,
prejudice, and irrationality, etc.