What is the common starting point of all arguments in each of the Five Ways?

Many of the great thinkers have tried to put an end to the perpetual question of God's existence. One of them is St. Thomas Aquinas. In his Summa Theologiae, St. Thomas presents the Quinquae Viae, or what we popularly know as The Five Ways. Here, we are not just presented with one but five philosophical explanations attempting to prove God's existence. Nevertheless, any theory would not have been formed without a foundation, without a basis. As observed and understood, St. Thomas' Five Ways were based from his observations and experiences of the world and the nature of things.

The first way is the argument from motion. This way tells us that God initiates or activates motion in the world. He is responsible for all the changes in things; but He, Himself, remains unchanged. The idea is taken from the nature of things that some things in the world are in motion; other things are at rest. If something is in motion, it is only because it is put into motion by something else.

The second way is from the nature of efficient cause. This way tells us that God is the first and primary cause. He is ultimately responsible for the existence of all the other intermediary causes that in turn are responsible for the various effects that we see in the world. Again, the idea is taken from the nature of things that any thing comes into being because it is caused by something else. Nothing is responsible for its own existence. Something has brought something into existence, into what it is.

The third way is from possibility and necessity. This way tells us that God is a being whose existence is necessary. He cannot not exist. And, He is inevitable in order to make sense of our empirical experience of the existence of things in the world. The idea is also taken from the natue of things that things are subject to generation and corruption. Whatever comes into being or begins to exist also goes out of being, into non-existence. We have to admit the existence of some being, having of itself its own necessity and not receiving it from another, but rather causing in others their necessity.

The fourth way is from the gradation to be found in things. This way tells us that God has all the perfection found in things. He is at the very top of the scale of existence and yet served as its very ground. Again, this idea is taken from the nature of things that there are things that are more or less beautiful than others. We describe and distinguish things as more or lesser than others because we have an idea of the maximum which we use as a basis for comparing things. In the hierarchy of beings, there must be one being that is supreme.

Lastly, the fifth way is from the governance of the world. This way tells us that God is supreme in knowledge and intelligence. He directs all things in the cosmos to their proper ends. This idea is also taken from the nature of things that things in the universe are governed. Things which lack knowledge are not capable of directional activity. Whatever lacks knowledge cannot move towards an end, unless it will be directed by some being endowed with knowledge and intelligence.