And, a summation of the argument for the existence of God::

1. He is first motion. Everything that is moving is moved by a mover. An infinite regress of movers is impossible. Therefore, there is an unmoved mover from whom all motions proceeds. This is God.

2. He is first cause. Everything that is caused is caused by something else. An infinite regress of causation is impossible. Therefore, there must be an uncaused cause of all that is caused. This is God.

3. He is first being. Everything of this universe has a transitory nature in which they exist and then fail to exist. Since it is impossible for these things always to exist, then it indicates a time when they did not exist. If there are things which are transitory then, at one time, there could have been nothing in existence. If there was a time that there was nothing, then that nothing could not have brought anything to existence. As shown by first cause, everything is contingent on a creator because there must be a necessary being whose existence is not dependent on anything. This is God.

4. He is the standard of perfection. Everything has a varying degree of perfection. Each assumes towards an existing ultimate standard of perfection by the creator. Therefore, perfection has a summit. This is God.

5. He is first design. Everything natural in the world acts towards a purpose and an end where an intelligent being guides all natural bodies towards that purpose and end. This is God.

- St Thomas Aquinas: Summa Theologica -