Vernon Bates views Christian apologetics as legitimization through a strategic articulation of legitimating formulas devised to counter threats to the religious person’s universe, and the attempt to reach a compromise and/or correlation with “material fact” as science presents it (Bates 1981, 80-82).
Legitimization for Christians has been a frequent struggle given advances within scientific and biblical scholarship (Bates 1981, 80). Many twentieth-century Christian theologians attempted to answer challenges raised to their orthodoxy by these domains, notably in higher criticism, biology (the theory of evolution), and geology (the age of the Earth and of the universe). This was demonstrated in Christians seeking new ways to reconcile faith with expanding knowledge of the world, and the origins of the Creation Science movement advocating the teaching of creationist views within public schools and textbooks. Bates engages how apologetics evolved within several schools of Christian thought and offers a range of their legitimizing formulas that show how partisans relate to the secular world and scientific (material) fact (Bates 1981, 80).
According to Bates, scientific legitimization is an apologetic approach seeking to compromise Christianity with material fact, in particular with the theory of evolution (Bates 1981, 81). Several schools have proposed legitimizing formulas in response to material facts: Modernism, Neo-orthodoxy, Neo-evangelism, Evangelicism, and Fundamentalism. Each finds itself within an increasingly secularized world that provides challenges to the Christian religion.
Modernism. Modernism developed within Europe during the late nineteenth century before entering into American theological seminaries (Bates 1981, 82-83). Modernist theologians have often been referred to as Protestant liberals given their position in Protestant theological circles. Modernist theologians are at the opposite end of the spectrum to the fundamentalists and believe it necessary to rethink and present Christianity in a form comprehensible to the modern world. They reject a literal interpretation of the Bible because much within it does not cohere with reason and scientific experience. They argue that faith cannot be only grounded on belief and the Bible, and it must consider reason and experience. Despite this perspective, modernist theologians maintain that Christ is the most perfect revelation of God.
Neo-Orthodoxy. Neo-Orthodox theologians agree that the Bible contains myths but still hold that these are God’s revelations of the truth concerning reality (Bates 1981, 83). They differ from modernists in that they do not reject biblical myths as falsehoods. They believe in taking the Bible seriously as a source for learning about God, Christ’s teachings, and the principle of love. They view evolutionary theory as a material fact compatible with their faith as it is consistent with belief in God for it was God’s method of creation. This approach allows the Neo-Orthodox to accommodate faith to accepted material fact.
Neo-Evangelicism. These are evangelical Christians who slowly began to accept the material fact of evolution (Bates 1981, 84-85). They place emphasis on the risen Christ and the importance of having a personal relationship with him. Christ is the Son of God, died, and was resurrected from the dead to atone for humanity’s sin. Salvation only comes through God alone, and faith is first and foremost dedication to a person (Christ) rather than to a set of rules. Neo-Evangelical theologians do not hold the Bible to be literally true and argue that experience must precede reason. They balance belief in the Bible and Christ with an openness to the material facts of science.
Evangelicism. The Evangelists emphasize salvation by faith in Christ’s atonement and through personal conversion (Bates 1981, 86). They hold to three major legitimizing formulas concerning material fact (evolutionary theory) and their Christian faith: progressive creation theory, the day-age theory, and gap theory. Progressive creation theory holds that God used occasional acts of creation by interjecting into the evolutionary process at points throughout the geological ages. Day-age theory forwards the idea of the “days” of creation (the Bible teaches that God created the universe in six days) may be interpreted as the “ages” of geology. The gap theory posits that the geologic ages occurred before the six days of creation which means that the processes of evolution occurred in the gap between Genesis 1:1 and 1:3. These theories gained traction as legitimizing formulas for evangelical Christians following the 1920s and are still held today.
Fundamentalism. This denotes a social-religious movement arising in response to modernist theology, evolutionary theory, and higher textual criticism. Fundamentalism is where the greatest possibility exists for conflict between accepted material fact and a strictly literal interpretation of the Bible (Bates 1981, 86-88). Fundamentalist theologians teach that the Bible is the literal and direct truth of God incapable of error. Anything diverging from this will lead one away from the truth of Christianity. Fundamentalists defend the Bible against any other form of knowledge that disagrees with it, whether that be science, history, or biblical criticism. Fundamentalist theologians are also required to contend with scientific discovery and accepted material fact. Two social movements arose in the form of the Anti-Evolution movement of the 1920s and the Creation Science Movement of the 1960s and 1970s. This group employs apologetics which argues that because the Bible is the true Word of God, evolution is false, and Bible science factual.
What is most helpful in Bates’s analysis is understanding how partisans of these schools of Christian thought have responded to material fact through apologetics. Apologetics forced Christians to look for new ways to reconcile faith with expanding knowledge of the world. The aforementioned schools reconciled faith and material fact by either  welcoming knowledge of material fact even if this knowledge is deemed conflicting with biblical claims (the Modernists),  rejecting all such knowledge of material fact wherever it is deemed incompatible with a particular view of the Bible (the Fundamentalists), or  to find a compromise in being open to material fact while also emphasizing Orthodox views of Christ, God, and the Gospel (the Neo-Orthodox, Neo-Evangelists, and Evangelists).
Bates, Vernon. 1981. “Christian Apologetics as Legitimation.” Humboldt Journal of Social Relations 8: 80-93. Accessed July 8, 2019. https://www.jstor.org/stable/23261597