Appendix 6 – Van Til’s Presentation of TAG

(Excerpted from ‘A Survey of Christian Epistemology’ (1969), pp.204-5)  Although this publication is still available second-hand, its contents are subsumed into more modern editions of Van Til’s work, notably The Defense of the Faith, Christian Apologetics and An Introduction To Systematic Theology.

Since the non-theist is so heartily convinced that univocal reasoning is the only possible kind of reasoning, we must ask him to reason univocally for us in order that we may see the consequences. In other words, we believe it to be in harmony with and a part of the process of reasoning analogically with a non-theist that we ask him to show us first what he can do. We may, to be sure, offer to him at once a positive statement of our position. But this he will at once reject as quite out of the question. So we may ask him to give us something better. The reason he gives for rejecting our position is, in the last analysis, that it involves self-contradiction. We see again as an illustration of this charge the rejection of the theistic conception that God is absolute and that he has nevertheless created this world for his glory. This, the non-theist says, is self-contradictory. And it no doubt is, from a non-theistic point of view. But the final question is not whether a statement appears to be contradictory. The final question is in which framework or on which view of reality—the Christian or the non-Christian—the law of contradiction can have application to any fact. The non-Christian rejects the Christian view out of hand as being contradictory. Then when he is asked to furnish a foundation for the law of contradiction, he can offer nothing but the idea of contingency.

What we shall have to do then is to try to reduce our opponent’s position to an absurdity. Nothing less will do. Without God, man is completely lost in every respect, epistemologically as well as morally and religiously. But exactly what do we mean by reducing our opponent’s position to an absurdity? He thinks he has already reduced our position to an absurdity by the simple expedient just spoken of. But we must point out to him that upon a theistic basis our position is not reduced to an absurdity by indicating the “logical difficulties” involved in the conception of creation. Upon the theistic basis it must be contended that the human categories are but analogical of God’s categories, so that it is to be expected that human thought will not be able to comprehend how God shall be absolute and at the same time create the universe for his glory. If taken on the same level of existence, it is no doubt a self-contradiction to say that a thing is full and at the same time is being filled. But it is exactly this point that is in question—whether God is to be thought of as on the same level with man. What the antitheist should have done is to show that even upon a theistic basis our conception of creation involves self-contradiction.

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. It is this too that we should mean when we say that we are arguing ad hominem. We do not really argue ad hominem unless we show that someone’s position involves self-contradiction, and there is no self-contradiction unless one’s reasoning is shown to be directly contradictory of or to lead to conclusions which are contradictory of one’s own assumptions.