Arguments for the existence of God

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.

Many people maintain that they have directly experienced the presence of God in their lives. For example, some attribute to God some intense emotions experienced, or striking insights gained, in response to prayer or worship. And some attribute the manner in which events in their lives have unfolded, or fortuitous coincidences in their lives, to the influence of God. However, atheists also experience intense emotional experiences, fortuitous coincidences, and striking insights, though never in response to prayer or worship.

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, which is often called fideism. These believers note that the Christian faith teaches salvation by faith. Were God's existence rationally demonstrable, faith in His existence would become superfluous. Therefore, if Christian theology is true, God's existence can never be demonstrated either by empirical means or by philosophical argument.

There are also several arguments against the existence of God. The most commonly used one is the problem of evil.