* Atheists use circular logic to "disprove" the existence of God. That is, they presuppose that God does not exist and then argue that all proofs for the existence of God must be flawed because He does not exist. Christians can use presuppositional apologetics to break the circle of the atheists' circular reasoning.

* Muslims also use circular logic to defend the Qur'an. They argue that the Qur'an is true because it is the Word of Allah, that it is the Word of Allah because it says so, and that we can rely on it because it is true. This is completely different from why the Bible is true.

* Evolutionists will claim that a fossil is millions of years old because that is the date given by radiometric dating; then state that it is reliable because they "know" that the fossil is millions of years old due to the strata in which it was found; additionally because the radiometric dating methods agree with each other, and date correctly materials which were historically dated by humans.