Presuppositionalism is a school of Christian apologetics that believes the Christian faith is the only basis for rational thought. It presupposes that the Bible is divine revelation and attempts to expose flaws in other worldviews.

It claims that apart from presuppositions, one could not make sense of any human experience, and there can be no set of neutral assumptions from which to reason with a non-Christian

Greg Bahnsen was one of Van Til’s greatest expositors. His book Always Ready: Directions forDefending the Faith is a treasure trove of biblical instructionanswering the Why and How of presuppositional apologetics. Here Bahnsendiscusses the transcendental trust of the method. For those not familiar withVan Til’s approach it can be much at first, but once you “get it” you realizethat you’re dealing with nuclear strength apologetics:

If the way in which people reason and interpret evidence is determined bytheir presupposed worldviews, and if the worldviews of the believer andunbeliever are in principle completely at odds with each other, how can thedisagreement between them over the justification of Biblical claims beresolved? It might seem that all rational argumentation is precluded sinceappeals to evidence and logic will be controlled by the respective, conflictingworldviews of the believer and unbeliever. However this is not the case.

Differing worldviews can be compared to each other in terms of the importantphilosophical question about the “preconditions of intelligibility” for suchimportant assumptions as the universality of logical laws, the uniformity ofnature, and the reality of moral absolutes. We can examine a worldview and askwhether its portrayal of nature, man, knowledge, etc. provide an outlook interms of which logic, science and ethics can make sense. It does not comportwith the practices of natural science to believe that all events are random andunpredictable, for instance. It does not comport with the demand for honesty inscientific research, if no moral principle expresses anything but a personalpreference or feeling. Moreover, if there are internal contradictions in aperson’s worldview, it does not provide the preconditions for making sense outof man’s experience. For instance, if one’s political dogmas respect thedignity of men to make their own choices, while one’s psychological theoriesreject the free will of men, then there is an internal defect in that person’sworldview.

It is the Christian’s contention that all non-Christian worldviews are besetwith internal contradictions, as well as with beliefs which do not renderlogic, science or ethics intelligible. On the other hand, the Christianworldview (taken from God’s self-revelation in Scripture) demands ourintellectual commitment because it does provide the preconditions ofintelligibility for man’s reasoning, experience, and dignity.

In Biblical terms, what the Christian apologist does is demonstrate tounbelievers that because of their rejection of God’s revealed truth, they have“become vain in their reasonings” (Rom. 1:21). By means of their foolishperspective they end up “opposing themselves” (2 Tim. 2:25). They follow aconception of knowledge which does not deserve the name (1 Tim. 6:20). Theirphilosophy and presuppositions rob one of knowledge (Col. 2:3, 8), leaving themin ignorance (Eph. 4:17-18; Acts 17:23). The aim of the apologist is to castdown their reasonings (2 Cor. 10:5) and to challenge them in the spirit ofPaul: “Where is the wise? Where is the disputer of this world? Has not God madefoolish the wisdom of the world?” (1 Cor. 1:20).

In various forms, the fundamental argument advanced by the Christianapologist is that the Christian worldview is true because of the impossibilityof the contrary. When the perspective of God’s revelation is rejected, then theunbeliever is left in foolish ignorance because his philosophy does not providethe preconditions of knowledge and meaningful experience. To put it anotherway: the proof that Christianity is true is that if it were not, we would notbe able to prove anything.

What the unbeliever needs is nothing less than a radical change of mind –repentance (Acts 17:30). He needs to change his fundamental worldview andsubmit to the revelation of God in order for any knowledge or experience tomake sense. He at the same time needs to repent of his spiritual rebellion andsin against God. Because of the condition of his heart, he cannot see the truthor know God in a saving fashion.

-Greg L. Bahnsen, Always Ready: Directions forDefending the Faith, 121-122.


Presuppositional vs Evidential


Sovereignty and Presuppositionalism

The Sovereignty of the Self-Contained God is the Starting Point of All Knowledge

This important book is an introduction into the problems of Christian philosophy. It focuses on the philosophical system of Dr. Cornelius Van Til, which in turn is founded upon the presuppositions of an infallible revelation in the Bible and the necessity of Christian theology for all philosophy.

Basic to this study is the belief that presuppositions of human thought in every field must be basically one in order to arrive at any concept which both validates biblical faith and human knowledge. The sovereignty of the self-contained God is the key to every field, in that only the God of Scripture makes all things possible and explicable and is thus the basic premise not only of theology, but of philosophy, science and indeed all knowledge. 

In that God is the Creator of all things. He is their only valid principle of interpretation, in that they derive both their existence and meaning from His creative act. This belief is herein set forth in terms of various aspects of human thought.

Basic to this study is the belief that such a philosophy finds consistent and able exposition in the writings of Cornelius Van Til. This work, therefore, is thus both an exposition as well of Van Til’s development of that philosophy, a school of thought to which the author subscribes.