The Existence of God: A Thomistic Perspective
Explanation
a) Contingency: The starting point is the finite duration of things. As things are generated and corrupted, they can both be and not be—that is, they are contingent.
b) The First Principle: A being limited in duration is caused by something necessary. St. Thomas uses temporal considerations to formulate and test this principle. Things were once possible not to be, and they will be corrupted and cease to exist. Therefore, it is evident that they are not necessary. If all things were merely possible, there would have been a time when nothing existed. But this cannot be true, because if there had been nothing, nothing could have come into existence, since nothing comes into existence except from something that already exists. Therefore, there must be something necessary.
c) Necessary Being: A key distinction is evident: anything necessary is either necessary due to another or not—that is, absolutely necessary.
d) Conclusion: We must conclude that a necessary being exists, which is not necessary due to another and is the cause of the necessity of others. The conclusion is the existence of a necessary being, not subordinate to any other being.
1 Antecedents: Distinction Between Contingent and Necessary Being
This distinction is modified based on existence. The distinction between essence and existence was brought to light by Arab philosophers, with Avicenna providing a demonstration based on this distinction. Maimonides, inspired by Avicenna, influenced St. Thomas, who also reasoned partly from the fact that there are contingent beings. This admits the possibility of three scenarios:
- No beings are born or perish.
- All beings are born and perish.
- Some beings are born and perish, and some do not.
The first case is not considered, since experience shows that beings are born and perish. The second case also fails upon examination. If all beings could be born and die, it would follow that at some point all beings would have perished. But if they fell into nothingness, they could never have returned to existence, and today nothing would exist. Now, we see that something exists. Therefore, the third hypothesis is true: some beings are born and perish, but there is one that is outside any possibility of destruction and has necessary existence: the First Being, God.
2 The Five Ways
a) The First Way (Motion): In a moving world, there are things that are moved but do not move themselves. Every thing in motion presupposes a mover, and an infinite regress of movers is impossible. The observation of motion leads to the admission of a First Mover, immobile—that is, God. This way comes from Aristotle.
b) The Second Way (Causality): In the world, there is an order of efficient causes. Each effect refers to a preceding cause, and an infinite regress is impossible. One must assume a First Cause, uncaused—God.
c) The Fourth Way (Degrees of Perfection): Beings are more or less beautiful, perfect, etc. But these degrees are always relative to a maximum. There must exist, then, a being that contains all perfections in the highest degree and is the cause of the partial perfections of other beings—a Supreme Being, God.
d) The Fifth Way (Governance of the World): All beings in the world, including those lacking knowledge, tend to fulfill their purpose and act intentionally. Things without knowledge do not tend to an end unless directed by something with intelligence. There must be an intelligent cause directing the world to an end. This being is called God.
St. Thomas’s arguments for God’s existence in the Five Ways follow this structure:
- A starting point: an observation of a natural phenomenon.
- Application of causality: every effect has a cause.
- Impossibility of an infinite regress of subordinate causes.
- Conclusion: the existence of a First Cause, possessing an attribute that denies the starting point’s characteristic, corresponding to God.
3 Concepts
God: For St. Thomas, God is subsistent being itself, because in God, essence and existence are identical. Unlike creatures, God is simple, perfect, infinite, and necessary.
Contingent Being: A contingent being is one that exists but may not exist, as its existence depends on the will of God. This concept is central to Christian thought and arises from the concept of creation.
Necessary Being: A necessary being cannot not exist; it exists necessarily. In Thomistic metaphysics, the being that exists by virtue of its essence is God.
Cause: Aristotle defines a cause as any condition necessary for a phenomenon to occur. He identifies four types of causes: material, formal, efficient, and final. St. Thomas accepts this classification but adapts it concerning God.