The Logic for God

For me, the existence of God is simply logical. When I look at the variety and intricacy of the universe, it's easier to believe that all this was created rather than it all happened by chance.

A friend of mine says that a similar logic led him to consider that there is a God: As an engineer who was taught that input > process > output, he saw the design of the universe (output) and it started him on the road to seeking the God behind it all (input).

If you are of a more philosophical bent, William Lane Craig offers these (more complex) Five Arguments for God:

The Cosmological Argument from Contingency
1. Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause.
2. If the universe has an explanation of its existence, that explanation is God.
3. The universe exists.
4. Therefore, the universe has an explanation of its existence (from 1, 3).
5. Therefore, the explanation of the universe's existence is God (from 2, 4).

The Kalam Cosmological Argument Based on the Beginning of the Universe
1. Everything that begins to exist has a cause.
2. The universe began to exist.
3. Therefore, the universe has a cause.

The Moral Argument Based upon Moral Values and Duties
1. If God does not exist, objective moral values and duties do not exist.
2. Objective moral values and duties do exist.
3. Therefore, God exists.

The Teleological Argument from Fine-tuning
1. The fine-tuning of the universe is due to either physical necessity, chance, or design.
2. It is not due to physical necessity or chance.
3. Therefore, it is due to design.

The Ontological Argument from the Possibility of God's Existence to His Actuality
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.

Read the whole article for Lane's defense of these arguments.