Anselm's Ontological Proof and Aquinas's Five Ways

Anselm of Canterbury and the Ontological Argument

The importance of Anselm of Canterbury lies primarily in his role as the first Christian theologian who attempted to provide a proof of the existence of God without recourse to faith or the Scriptures. This test subsequently became known as the Ontological Argument.

Anselm's argument intends not to rely on data derived from faith, but it utilizes the notion of God—understood as “a being than which nothing greater can be conceived”—a notion that is already present in the mind.

We think of God as that than which nothing greater can be conceived. The atheist denies that God exists, but even the atheist must admit that the concept of God, as a mere idea, is already in the mind (in intellectu). However, if God is that than which nothing greater can be conceived, God must exist both in the mind and in reality; otherwise, we could conceive of something greater: a being with all the attributes of God that also exists in reality. The problem remains whether, in establishing this notion of God, we are only uttering a word or if the concept is truly present in the mind.

Natural Theology and Proofs of God's Existence

Natural Theology refers to truths about God that can be discovered by reason outside of faith. The first and most fundamental of these truths is that God exists, which is demonstrated through the Five Ways.

Types of Arguments for God's Existence

• Arguments A Priori: These disregard experience, considering that the existence of God is shown from his own essence (e.g., Anselm's argument).
• Arguments A Posteriori: These begin with a fact derived from experience (e.g., Aquinas's Five Ways).

Thomas Aquinas's Five Ways

The Five Ways are proofs of God's existence based on empirical observation of the world:

1. The Argument from Motion (Prime Mover)

   Given the existence of motion in the world, we conclude that God is the Prime Mover Unmoved. Everything that is moved must be moved by something else, leading to an infinite regress unless there is a first, unmoved mover.

2. The Argument from Efficient Causality

   This relies on the concept of efficient causality. Nothing in the world is the cause of itself. There must be a first efficient cause that is uncaused: God.

3. The Argument from Contingency (Necessary Being)

   Given that the beings of the world are contingent (they can either exist or not exist), we conclude that God is a Necessary Being. If everything were contingent, there would have been a time when nothing existed. If at some point there was nothing, then nothing could have come into existence. This is absurd. Therefore, there must be a being necessary in itself: God.

4. The Argument from Degrees of Perfection

   Recognizing that there are degrees of perfection in things (goodness, truth, nobility), we conclude that God is the cause of these perfections. If things possessed perfection by nature, they would have it in the fullest degree. Since they do not, they must receive perfection from another source, which must be absolutely perfect: God.

5. The Argument from Teleology (Intelligent Designer)

   Based on the ordering of the universe toward an end (purpose), we conclude that God is the First Ordering Intelligence. Beings lacking intelligence (like natural bodies) develop toward a specific end. Since they cannot know this end themselves, this order must come from an intelligent being: God.