Simply put, circular reasoning is an attempt to support a statement or claim by repeating it in different or stronger terms. Circular reasoning is false logic, and it shows up in many fields where assumptions and presuppositions are made. A classic example is the evolutionist’s dating of fossils according to the rock strata they are found in, while at the same time dating the strata according to the “index fossils” they contain. Dating a rock based on the fossil it contains only works if it is assumed that evolution is true. As one paleontologist admitted, “For most biologists, the strongest reason for accepting the evolutionary hypothesis is their acceptance of some theory that entails it” (David G. Kitts, “Paleontology and Evolutionary Theory,” in Evolution, September 1974, p. 466).
Christians, too, sometimes resort to circular reasoning. The statement “I believe the Bible is true because the Bible says it is true” may make perfect sense to a believer—it is a faith-based statement—but in a logical argument it would be considered circular reasoning. The claim uses its claim to prove its claim. Skeptics and critics of Christianity often allege that Christians use circular reasoning to defend their biblical beliefs. Such criticisms are largely untrue; however, we should be careful to use valid reasoning methods in support of truth.
Another example of circular reasoning relates to God’s existence. Some Christians have argued that God exists because the Bible says God exists—and, since God wrote the Bible, it must be true. This argument is problematic from a purely logical standpoint since it bases belief in God’s existence on the Christian belief that the Bible comes from God.
The Bible does assume the existence of God, and it does claim to be the truth (Genesis 1:1; Psalm 33:4). Those statements must be taken on faith, which should surprise no one. The Bible says faith is required. Without faith, it is impossible to please God, and faith is the foundation of the Christian life (Hebrews 11:6; Romans 1:17).
At the same time, there are many solid, logical arguments to build a plausible case for Christian belief. The existence of God can be deduced from the existence of creation (Psalm 19:1), and the veracity of the Bible through historical evidences (John 10:37–38). Circular reasoning is unnecessary. We can utilize a combination of biblical data, logical reasoning, philosophy, and historical and scientific evidence to present the best possible case regarding Christian teaching. Many Christian authors have written defenses of the faith, including C. S. Lewis, Josh McDowell, Lee Strobel, Norman Geisler, and more.
The Bible challenges Christians to be prepared to explain the hope we have. “Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect, keeping a clear conscience, so that those who speak maliciously against your good behavior in Christ may be ashamed of their slander” (1 Peter 3:15–16).
Ultimately, the Bible must be accepted by faith, and it is only the Word of God that has the power to change lives (John 17:17). Can a person be brought closer to the truth through logical reasoning? Yes. Can a person accept the truth of Christianity without faith? No.