St. Thomas Aquinas’s Five Proofs for God’s Existence

Summary

In his work *Summa Theologica*, St. Thomas Aquinas presents five arguments to prove God's existence. These include the Argument from Motion, Causation, Contingency, Degrees of Perfection, and Final Causes (or Design). Aquinas argues that everything in the world is either moved or caused by something else, leading to the conclusion that there must be a first, uncaused mover or creator—God. He also asserts that the presence of perfection, purpose, and order in the world points to an intelligent designer, further reinforcing the belief in God’s existence.

Takeaways

• 😀 Aquinas' five proofs for God's existence are presented in his work *Summa Theologica*.
• 😀 The arguments draw from human experience and Aristotle’s philosophy, especially his concept of the four causes.
• 😀 The first proof is the Argument from Motion, which states that a first, unmoved mover (God) must exist to initiate movement.
• 😀 The second proof is the Argument from Causation, arguing that every effect has a cause, ultimately leading to an uncaused cause (God).
• 😀 The third proof is the Argument from Contingency, which claims that there must be a necessary being (God) for contingent beings to exist.
• 😀 The fourth proof is the Argument from Degrees of Perfection, suggesting that the existence of a standard of perfection implies the existence of a perfect being (God).
• 😀 The fifth proof is the Argument from Design (Teleological Argument), which argues that the purposeful design of the world indicates a designer (God).
• 😀 The Argument from Motion explains that everything in motion was put into motion by something else, necessitating a first unmoved mover.
• 😀 The Argument from Causation builds upon Aristotle’s concept of efficient causes, concluding that there must be a first cause (God).
• 😀 The Argument from Contingency asserts that the existence of necessary and possible beings points to the need for a necessary being (God) to begin existence.

Q & A

What is the main source for St. Thomas Aquinas' five proofs for the existence of God?

The main source for St. Thomas Aquinas' five proofs is his work *Summa Theologica*.

How does the argument from motion lead to the conclusion of a first unmoved mover?

Aquinas argues that everything in motion must have been set in motion by something else. This creates an infinite chain of movers, but for the series to begin, there must be a first, unmoved mover, which he identifies as God.

What does the argument from causation emphasize about the chain of causes?

The argument from causation emphasizes that everything in the world has a cause, but an infinite regress of causes is illogical. Therefore, there must be a first uncaused cause, which Aquinas attributes to God.

What distinction does Aquinas make in the argument from contingency?

Aquinas distinguishes between necessary beings, which must exist, and possible beings, which could either exist or not. He argues that for contingent beings to exist, there must be at least one necessary being, which he identifies as God.

How does Aquinas use the concept of perfection in his fourth argument?

In the argument from degrees of perfection, Aquinas explains that humans judge things based on perfection. He argues that there must be a being that is the ultimate standard of perfection, and this being is God.

What is the basis for the teleological argument or the argument from final causes?

The teleological argument is based on the idea that everything in the world, including humans, acts according to a design with a purpose. Since these beings cannot design themselves, there must be an intelligent designer, which Aquinas identifies as God.

How does Aristotle’s concept of the four causes influence Aquinas’ arguments?

Aquinas' arguments are influenced by Aristotle’s concept of the four causes, especially the concepts of efficient cause, final cause, and motion, which Aquinas uses to demonstrate the necessity of a first cause, a first mover, and an ultimate designer.

Why is the argument from contingency considered one of Aquinas' key proofs for God's existence?

The argument from contingency is key because it establishes that the existence of contingent beings requires the existence of a necessary being, and Aquinas argues that this necessary being is God.

What role does the idea of perfection play in proving God's existence according to Aquinas?

The idea of perfection serves to show that humans must have a standard of perfection to compare things. Since this standard of perfection cannot come from imperfect beings, Aquinas concludes that the ultimate perfect being is God.

How does Aquinas' view of design in the natural world support his argument for God's existence?

Aquinas argues that the purposeful design seen in nature—such as birds' wings for flight or humans' use of speech—points to an intelligent designer, as only a being of greater intelligence could guide these beings toward their end. This designer is God.