Sufficiency, Necessity, and Transcendental Arguments

One of the most foundational claims of the Van Tillian school of presuppositional apologetics is that the Christian worldview is the necessary precondition for the intelligibility of human experience. This means that the set of presuppositions that make up the Christian view of reality, knowledge, ethics, man, God, etc. are necessary for human experience to make sense. The claim is that we cannot make sense of the world, or know anything about it, without presupposing, at least implicitly, the Christian worldview. This is the so-called Transcendental Argument for God (TAG).

This is a bold claim to say the least, and it has definitely not gone uncriticized. One of such criticisms concerns the mere sufficiency of the Christian worldview. Another such criticism is concerning the possibility of a uniqueness proof for the Christian worldview. These objections are not unique to TAG, though. They have their roots in the much broader list of objections raised against transcendental arguments in general. Basically, the first criticism is that even though Christian Theism is a sufficient condition for the intelligibility of human experience, that does not prove that it is a necessary condition. The second criticism is that it is impossible to formulate a proof of the uniqueness of Christian Theism with regards to providing the preconditions of intelligible human experience. This is due to there being a potentially infinite number of competing schemes all of which would have to be refuted before it can be shown that Christian Theism uniquely provides the preconditions necessary for intelligible human experience. These criticisms are very similar, so I will attempt to answer both these criticisms with a few observations. Before that, however, it is important to examine the distinction between sufficient and necessary conditions.

A necessary condition is simply a condition that must be met in order to explain something. For example, eggs are a necessary condition for making omelette - you cannot make omelette without eggs. However, eggs are not sufficient to make omelette - butter, oil and a frying pan are also needed. Taken together, however, they constitute sufficient conditions for making omelette. Necessity does not imply sufficiency, and sufficiency does not imply necessity.

We can think of transcendental analysis as attempting to discover the transcendental worldview. A transcendental worldview would be a set of transcendental presuppositions. Transcendental presuppositions would be presuppositions that are necessary conditions of intelligible human experience. If transcendental presuppositions are presuppositions that are necessary conditions of intelligibility, it follows that there can be only one set of transcendental presuppositions. If there were other presuppositions that provided the conditions, these presuppositions would cease to be necessary. If you could make omelette without eggs, eggs would cease to be a necessary condition for making omelette. What follows from this, then, is that there can only be one transcendental worldview. Hence, if a certain worldview is sufficient in terms of providing the conditions for human experience, then that worldview must also be necessary. In terms of transcendental analysis, sufficiency implies necessity. 

What is the relevance of this with respect to the initial criticisms? It implies that Christian Theism cannot be merely sufficient - if it is sufficient, then it is also necessary. This answers the first criticism. It also implies that a uniqueness proof of Christianity is possible. In order to demonstrate that Christian Theism  uniquely provides the preconditions of intelligible experience, one need only demonstrate the sufficiency of the Christian worldview. When we show that Christian presuppositions are sufficient to provide the preconditions of intelligible human experience, we are inadvertently showing that it does so uniquely. This answers the second criticism. We do not have to refute a potentially infinite number of competing worldviews in order to show that Christianity is necessary - all we need do is to show that Christian beliefs sufficiently account for intelligible experience.

There is, however, one final objection that can be raised here. It can be claimed that sufficiency does not imply necessity since there can be a plurality of sufficient worldviews. That is, why think that there must be a transcendental worldview in the first place? Our response to this objection is two-fold.

Firstly, positing a plurality of sufficient worldviews leads to a problem of underdetermination. This means that incompatible and contradictory worldviews would have to be treated as equally valid with no way of choosing between them. Transcendental analysis is a means of adjudicating between competing worldviews but if we accept pluralism, then no such adjudication is possible. It leads us to the absurd conclusion that contradictory systems can both prove sufficient for our intelligible experience.

A second way we can answer this objection is by arguing that we can only know one worldview/conceptual scheme. If there were other schemes which were so different from our own, we would not be able to recognize them as competing schemes. Before we can recognize competing schemes, we must be able to compare them with the scheme we do possess. If a scheme was so different from ours that no comparison could be made, then we would be unable to recognize it as a competing scheme. This implies that we can only know one worldview. This worldview, then, must be the transcendental worldview.