Norman Geiser’s masterful work, Christian Apologetics, is a very thorough textbook that builds a strong epistemological foundation before even addressing Christian truth. Geisler’s initial goal is to establish an adequate test for truth, and from there to show that the Christian worldview meets the tests for truth. Because of this, the book covers over a half a dozen alternate view before even evaluating theism.
First, Geisler shows the shortcomings of agnosticism. He critiques the views of Kant, Hume, Ayer, and Wittgenstien. Following the critique of agnosticism comes the evaluation of rationalism. The views of Descartes, Spinoza, Leibniz, Hackett, and Clark are examined. Next comes an inspection of fideism. Here Pascal, Kierkegaard, Barth, and Van Til are summarized and critiqued as adherents to various strands of fideism.
Geisler continues in his worldview analysis by looking at experientialism, evidentialism, and pragmatism. Again, the author’s goal in presenting each of these views is to examine its core epistemology and to find out what its test for truth is. Geisler shows that rationalism, fideism, experientialism, evidentialism, combinationalism, and pragmatism all fall short as adequate tests for truth. Each of them may have elements that are useful in one sense or another, but none of them is a fully adequate test for truth.
Before Geisler launches into theism, he does lay out what he presents as an adequate test for truth. First, he presents unaffirmability as a test for falsity. That is to say: if a view is self-defeating, whether directly or indirectly, it must be false. Second, Geisler presents undeniability as a test for truth. If something is either definitionally undeniable or existentially undeniable, it must be true. These two tests are for the truthfulness of a worldview. Once you establish the correct worldview, then you can move on to determine the test for truth within that worldview. For this internal test, Geisler presents systematic consistency as the test for truth for statements within a worldview that has first been established through the tests of unaffirmability and undeniability. Systematic consistency means that whatever most consistently and comprehensively fits into that system is true. Geisler admits that systematic consistency does not provide absolute certainty of truth. Here he points to probability as the guide, as absolute certainty is not possible when a finite mind is not in possession of all the facts.
Having laid a very thorough epistemological base, the author then proceeds to establish the truthfulness of Christianity. The worldviews of deism, pantheism, panentheism, atheism, and theism are compared. Using the aforementioned tests for truth for each of these worldviews, theism wins out. With theism established through a very methodological evaluation of each competing worldview, Geisler then builds on the theistic worldview.
Now Geisler builds the case for the historical reliability of the New Testament. After showing that the New Testament is an accurate picture of Jesus, he makes the case for the deity and authority for Jesus Christ. And finally, with the Lordship of Christ established, a case can be made for the inspiration and authority of the Bible as a whole.
This review has attempted to paint an overall flow of Geisler’s apologetic system. It truly is thorough. Christian Apologetics is not light reading, as it deals heavily with philosophical foundations and epistemological concerns from the outset. However, Geisler has succeeded in authoring a comprehensive text for establishing a complete and systematic framework for Christian apologetics. This text can be commended as required reading for any serious student of apologetics.