In chapter three, Apologetic Method: Evaluating Worldviews, Groothius states that apologetics means philosophical engagement, and philosophy trades on logic. Groothius provides a brief discussion on some basis logical principles. Groothius believes in the laws of logic which are not just good ideas.
Laws of Logic: Not Just Good Ideas, But The Law
The first law or principle of logic is the law of noncontradiction which states “Nothing can both be and not be at the same time in the same respect” (Aristotle Metaphysic 1005, b19-20). For example, Jesus cannot be both sinless and sinful. If there is exactly one God, there cannot be many gods.
The law or principle of excluded middle trades on the same essential insight as the law of noncontradiction. Jesus assumes this principle when he warns that “no one can serve two masters. Either you will hate the one and love the other, or you will be devoted to the one and despise the other. You cannot serve both God and money” (Matthew 6:24).
The law or principle of bivalence states that any unambiguous declaration statement is either true or false---not neither true or false and not both true and false.
The law or principle of identity simply states that something is what it is: A = A. I cannot be fifty-one years old and fifty-five years old at the same time.
These laws of logic fit the biblical claim that all humans are made in the divine image and so think in essentially similar way. This fact should give us confidence to develop a fundamental apologetic method that trades on logic and develops arguments rationally.
Worldview Hypothesis Evaluation
A worldview hypothesis is a broad-ranging theory of everything, in that it tries to account for the nature and meaning of the universes and its inhabitants. Groothius provides eight tests for any worldview hypotheses.
The first criterion is that it explains what it ought to explain. If and X is utterly mysterious or unintelligible and sheds no light on anything (it is a bare assertion), then the assertion of X is a rational strike against that worldview.
Sure, the Trinity is mysterious but is also a biblical definition of one God and three persons who each is deity.
The second criterion is internal consistency. If a worldview affirms X, Y, Z as essential elements of that worldview, and none of these individual elements contradicts another essential element, the worldview may be true because it is not logically inconsistent.
The third criterion coherence. if a worldview’s essential propositions are coherent (meaningfully interconnected conceptually), it is more likely to be true than if its essential propositions are not related in this way.
The fourth criterion is factual adequacy. The greater the extent to which a worldview’s essential factual claims can be established in various empirical, scientific and historical ways, the greater is the likelihood that this worldview is true.
The fifth criterion is existential viability. For a worldview to be a likely candidate for truth, its essential proposition must be existentially viable.
Christian Science and New Age spirituality believe that there is no objective evil in the world, that evil is all in the mind or only a lower form of consciousness. Rape or murder, therefore, cannot be condemned as truly evil
The sixth criterion is intellectual and cultural fecundity. If a worldview is true, it should lead to intellectual and cultural fecundity. The greater the beneficial fecundity, the greater evidence that that worldview is true.
This criterion must agree with the other criteria. Islam is growing but it contradicts other criteria.
The seventh criterion is radical ad hoc readjustment. If a worldview substantially alters its essential claims in light of counterevidence, it loses rational justification.
Open theism is an ad hoc or improvised readjustment on the nature of God to address the problem of evil.
The eight criterion is all things being equal, simpler explanations are preferable to unnecessarily complex ones. Worldviews should not appeal to extraneous entities or be more complex than is required to explain what they propose to establish.
The cumulative effect of these eight criterion is that theism is most verifiable worldview.
Other Apologetic Systems
Fideism is an attempt to protect Christian faith against the assaults of reason by means of intellectual insulation and isolation. All fideists reject natural theology. The Reformed view of faith as a divine gift preceding regeneration fits here. Groothius states that Kierkegaard was a fideist and presents an insightful psychological apologetic in many of his works, particularity The Sickness Unto Death---a work that helped Groothius become a Christian in 1976.
Presuppositionalism claims that the Christian should presuppose the entire Christian worldview and reason from this conviction with unbelievers. Van Til rejects using logic and evidence in defending truth or God existence. If this is true, then all apologetics and theology must be rejected. Gordon Clark, a presuppositionalist, however, insisted that the law of noncontradiction was a necessary and negative test for truth. Presuppositionalists are inconsistent when they use negative apologetics to tear down non-Christian worldviews but will not use positive apologetics to defend theism.
Reformed epistemologists argue that secular thought has placed an undue burden on Christian apologetics. It demands that Christians offer proof for their beliefs on pain of being irrational. Positive arguments are not required for warranted belief in God or for Christian theism. Alvin Plantinga argues that the Christian worldview provides the metaphysic required for this epistemology. As long as there are no in-principle reasons not to believe in Christianity---that is, as long as belief in Christianity is not shown to be intrinsically irrational ---one may believe the Christian faith rationally. One comes to believe in the inspiration of Scripture simply because the Bible is “self-authenticating” to those who believe through the Spirit.
Evidentialism is a method in apologetics that argues that the most significant historical events in Christianity---particularly the resurrection of Jesus---are matters that can be established through proper historical argumentation, even apart from any prior arguments for the existence of God. Classical apologists argue first for the existence of a monotheistic God and then argue for the particulars of Christianity---the reliability of the Bible and the claims and credentials of Jesus. Classical apologists employ this two-step strategy. Evidentialism has a one-step strategy where a die-hard naturalist will convert to Christianity in one-step. Groothius argues it is possible to be convinced from the evidence for the resurrection of Jesus and still not have an overall Christian worldview. For example, Jewish New Testament scholar Pinchas Lapide argues for the literal resurrection of Jesus but believes that Jesus is the Savior only of Gentiles, not of Jews, who continue to have their own separate covenant.
The Limits of Apologetics
First, the Bible is a long, ancient and sometimes perplexing book for contemporary people. To hold that the Christian worldview is the best rational explanation for the things that matter most does not imply that we have a lock on all the best arguments or have attained all the truths we need.
Second, apologetics is limited not only by the difficulty of the subject itself, but by the weaknesses of the subjects who practice it---us. We are the medium for this matchless message, but we are flawed.
Third, apologetics must be understood within the framework of God’s secret councils, as Calvinists like to put it. God, in his ordinary providence, maketh use of means, et is free to work without, above, and against them, at his pleasure (Wetminster Confesssion of Faith 5.3).
Summary: A Cumulative and Winsome Approach
Groothius says that in his book he “will offer a variety of arguments that verify or confirm the Christian worldview as superior to its rivals, thus showing that Christianity alone makes the most sense on the things that matter most.