One of the arguments for the existence of God that many Christians are unfamiliar with is the transcendental argument (TAG). Too often descriptions of this argument make it sound complicated but (like most philosophical arguments) it is generally understandable once you have the basic idea. Because it is such an interesting (and I think useful) argument I would encourage more Christians to be familiar with it. For that reason, I am going to attempt a simple explanation of what it is and how it works. If you are already familiar with all of this you can certainly find more detailed discussions about it elsewhere, but if you are not familiar with TAG I pray this will be helpful to you.
The term Transcendental Argument does not refer to any single argument, but rather to a particular type of argument. A transcendental is something that goes beyond (transcends) particular facts, thoughts, or knowledge but are necessary to them. A transcendental argument begins with a given fact or state of affairs and then argues from it for the truth of those conditions that are necessary for that fact or state of affairs to be the case. To put it another way, a transcendental argument makes the logical claim that (A) is necessary for (B) to be the case therefore if (B) is the case, (A) must also be the case.
Transcendental arguments for the existence of God are arguments for the impossibility of the contrary. They try to show that God must exist because if He did not the world we live in would be impossible. The argument attempts to demonstrate that the unbeliever, based on their own worldview, has no rational foundation for logic, mathematics, science, ethics, and other necessary preconditions for knowledge. By appealing to and/or utilizing any of these without being able to provide an adequate foundation for them the atheist is being inconsistent and therefore irrational. Rather than arguing with an unbeliever about the interpretation of any particular fact or evidence TAG challenges the unbeliever to explain how they can explain (on the basis of atheism) the very methods they want to use to evaluate facts and evidence to begin with.
Perhaps some examples would be helpful. Given the space constraints here I can only give a couple of extremely simplified examples but if you are interested in learning more I suggest you click on the recording below of the debate between Dr. Stein and Dr. Bahnsen and pay attention to the way Dr. Bahnsen is arguing. This is a classic example of TAG by a skilled debater.
Unbelievers often try to use the problem of evil to argue against God but an atheistic system cannot provide any foundation for absolute moral judgments such as good or evil. By using the problem of evil, they are inappropriately importing a theistic concept into a worldview where it can have no logically consistent meaning.
Many atheists love to talk about how logical they are and how illogical Christians are and all atheists use logic (it is impossible to think, know, or communicate anything without it) but an atheistic worldview cannot account for laws of thought that are necessary, universal, and unchanging. They may be able to show why laws of thought could be universal but not necessary or unchanging. Therefore, the very fact that atheists can think is inconsistent with their worldview.
There have been various criticisms against TAG but by far the most common is that it is simply begging the question. Despite the popularity of the accusation that TAG is simply an example of circular reasoning the criticism fails to distinguish between the assumption of first principals and the premises of a particular argument. Those who are interested can find an excellent explanation of why this accusation is an overstatement at James Anderson’s site HERE. The other criticisms are far less common and more sophisticated so I am not going to try and handle them here.
The bottom line is that the Transcendental Argument for the existence of God simply holds that the non-existence of God is impossible because without Him we have no adequate foundation for knowledge itself. It is a challenge to unbelievers to demonstrate how their worldview can support necessary, universal, and unchanging laws of thought and morality or how they can support the assumptions of causality and uniformity that science assumes. It argues that these things are ultimately dependent upon a theistic worldview and before unbelievers can argue against theism based on what they presume to know, they must first explain how it is that they can justify knowledge itself on the basis of their view. If you are interested in the Transcendental Argument then it will be well worth your time to watch the video below to see how Dr. Bahnsen develops and uses the argument against Dr. Stein.
The “Great” Stein, Bahnsen Debate