The following is from Van Til’s response to Herman Dooyeweerd’s contribution to ‘Jerusalem and Athens’
I say, therefore, to those who ask about the Christian system somewhat as follows: “You, my friends, state and defend or reject what you call systems of reality and knowledge. Well, I too have a ‘system,’ but it is a different kind of system. It is neither a deductive nor an inductive system, in your sense of the term. Nor is it a combination of these two. My ‘system’ is not that of empiricism, of rationalism, of criticism, or of any of the other ‘systems’ you may read about in the ordinary texts on philosophy. Nor is my ‘system’ a synthesis between one of your systems with that of the Bible. My ‘system’ is attained by thinking upon all the aspects of reality in the light of the Christ of Scripture. I try to think God’s thoughts after him. That is to say, I try as a redeemed covenant-creature of the triune God to attain as much coherence as I, being finite and sinful, can between the facts of the universe. God’s revelation is clear, but it is clear just because it is God’s revelation and God is self-contained light. My ‘system’ is therefore an analogical reinterpretation of the truth that God has revealed about himself and his relation to man through Christ in Scripture. I construct my ‘system’ by means of a variety of gifts that God has created within me. Among these gifts is that of concept-formation.
– Cornelius Van Til, Jerusalem and Athens p.126
“Our wisdom in so far as it ought to be deemed true and solid wisdom, consists almost entirely of two parts: the knowledge of God and of ourselves. But as those are connected together by many ties, it is not easy to determine which of the two precedes, and gives birth to the other. For, in the first place, no man can survey himself without forthwith turning his thoughts toward God in whom he lives and moves; because it is perfectly obvious, that the endowments which we possess cannot possibly be from ourselves, nay, that our very being is nothing else than subsistence in God alone.” – (John Calvin, The Institutes of the Christian Religion. 1.1.1)
From this quotation, certain things are clear. Calvin never did start a chain of reasoning about man’s nature and destiny by taking man by himself. He did not start with man as with an ultimate starting point. Calvin did start with a general a priori position. His position is as radically opposed to that of Descartes as it is to that of Hume. Most apologetic writers who have come after Calvin have allowed themselves to be influenced unduly by Cartesian philosophy on this matter. Calvin recognized fully that if man is to have true knowledge of himself he must regard God as original and himself as derivative. He did not place God and man as correlatives next to one another, but he recognized from the outset two levels of existence and two levels of interpretation, on the one hand the divine and eternal, and on the other hand the human or temporal. To him it is perfectly obvious that the endowments that we possess are not of ourselves, but of God. Hence he says that “not a particle of light, or wisdom, or justice, or power, or rectitude, or genuine truth, will anywhere be found, which does not flow from him: and of which he is not the cause.”
– Cornelius Van Til, An Introduction to Systematic Theology p.156-157
It is customary on the part of some orthodox theologians to depreciate the objects of sensation as a source of knowledge. They have become deeply convinced of the scepticism involved in historical empiricism. They would therefore substitute an a priori approach for that of the empiricist, thinking that thus they represent biblical thought.
Two points may be mentioned with respect to this. In the first place, to flee to the arms of an apriorism from those of empiricism is in itself no help at all. It is only if an a priori is self-consciously based upon the conception of the ontological Trinity rather than upon the work of Plato or some other non-Christian philosopher that it can safeguard against scepticism. The a priori of any non-Christian thinker will eventually lead to empiricism. It can keep from doing so only if it keeps within the field of purely formal predication. In the second place, if we do place the ontological Trinity at the foundation of all our predication then there is no need to fear any scepticism through the avenue of sense. Sensation does “deceive us” but so does ratiocination. We have the means for their corruption in both cases. The one without the other is meaningless. Both give us true knowledge on the right presupposition; both lead to scepticism on the wrong presupposition.
– Cornelius Van Til, An Introduction to Systematic Theology p.123-124