In an attempt to offer proof for the existence of God, Thomas Aquinas developed a systematic theoretical approach. This rational argument, known as the Cosmological Argument for the Existence of God, looks at the complexity of nature and being and concludes that a deity known as the Prime Mover, First Cause, and Divine Designer is responsible for the existence of the universe.

If something is finite, it has a beginning. Because of the universal law of causation, we know that in order for something finite to have its beginning, something had to be there to do the starting. In our physical realm, we see evidence of finite existence all around us. The universe started from a single point and is expanding. Much of what was there in the beginning has decayed. Our earth will someday be destroyed when the Sun explodes. If the sun doesn't explode, but instead loses its ability to provide the necessary level of heat earth requires for life, then the earth will freeze over and life on earth will likely cease to exist. The start-to-end path of finitude is an absolute. We have not seen evidence in the physical realm of anything that defeats this trend.

Since the universe appears to have a beginning (Big Bang), the mystery is what was it that provided the starting of the Big Bang? If something else finite was identified as the starter, then that finite object would have to have a starter as well, and if that starter was finite...and so on. This is what is known as infinite regression. It is an endless series of finite events being started by finite objects.

Some scientists believe that until technology is more advanced, we will just have to maintain as a mystery that which existed prior to the Big Bang; hence, the starter. But some scientists, philosophers, and theologians hold to the theory that something infinite must have started the Big Bang.

Without any knowledge of the Big Bang, Thomas Aquinas defined this Infinite Starter as though Aquinas was familiar with the Big Bang. Aquinas stated that a Primer Mover put things into motion, a First Cause is responsible for the initial causation, and as contingent beings, there must be a Necessary Being.

Aquinas took it a step further in an attempt to show that our existence has a personal touch. He argued that complexity of our reality demonstrates purposive design, and thus labeled God as the Divine Designer. This is known as the Teleological Argument or Design Argument for the existence of God. Aquinas stated that purposive design could not have occurred by accident.

Today, advanced scientific technology, theoretical physics, chemistry, and biology have uncovered a more detailed understanding of our existence. To some people, these details result in the Anthropic Principle: an understanding that the successive stages that led to life faced extreme odds, and these odds could not have been overcome naturally. Thus, a Divine Designer was responsible for the incredible complexity of nature and life.

For more on the Anthropic Principle, read the article entitled Anthropic Assessments.