Arguments for the existence of God that have been made over the years include:
- the ontological argument, based on arguments about the "being greater than which nothing can be conceived"
- the cosmological argument, which argues that God must have been around at the start of things in order to be the "first cause"
- the teleological argument, which argues that since the universe is highly non-random, it must have been designed by an intelligent designer, God
- argument from common consent: people in all times and places have believed in God, so who are you to disagree
- argument from morality: supposes that morality cannot exist without God, therefore God must exist
- transcendental argument for the existence of God: supposes that logic, science, ethics, and other good things don't make sense if there is no God. Therefore arguments against the existence of God must ultimately refute themselves if pressed with rigorous consistency.
- Christological argument is specific to Christianity: asserts that Jesus Christ's life as written in the New Testament establishes his credibility, so we can be sure of the truth of his statements about God.
- Pascal's wager attempts to use game theory to show that belief in God represents the best and safest strategy of belief.
The theological standing of arguments for the existence of God is also subject to some debate among believers. Within the Christian tradition there are two sharply opposed viewpoints. The Catechism of the Catholic Church, following the Thomist tradition of St Thomas Aquinas, affirms that it is a doctrine of the Roman Catholic Church that God's existence can in fact be rationally demonstrated. Other Christians in different denominations hold similar views. On the other hand, some believers hold a contrary position. These believers note that the Christian faith teaches salvation is by faith, and that faith is reliance upon the faithfulness of God, which has little to do with the believer's ability to comprehend that in which he trusts. In other words, if Christian theology is true, then God's existence can never be demonstrated, either by empirical means or by philosophical argument. The most extreme example of this position is called fideism, which holds that faith is simply the will to believe, and argues that if God's existence were rationally demonstrable, faith in His existence would become superfluous.