Classical Arguments for God's Existence

Traditional Proofs of the Existence of God

Principle of Causality (Aquinas's Five Ways)

Everything that moves is moved by another. We cannot trace this series of causes infinitely backward; therefore, there must be an uncaused first cause, which is God. Similarly, the universe exhibits a complex design, implying a designer we call God. A key problem with these arguments is that they use the principle of causality to establish the existence of an exception to the principle itself.

The Ontological Argument

The ontological argument centers on the idea of God as "that than which nothing greater can be conceived." If we conceive of God, we cannot conceive of God as non-existent, because a non-existent being is less great than one that exists. This leads to a contradiction: conceiving of something greater than what we conceive. This argument was influential, but it is considered invalid because it attempts to move from a concept in the mind to existence in the real world (Popper's critique: it tells us nothing about the real world).

Kant's Moral Argument

Immanuel Kant concluded the existence of God as the guarantor of the moral law and the ultimate provider of justice. This argument is problematic because it assumes the existence of God as the source of the moral law, which is precisely what the argument seeks to prove.

The Wonder of the Existence of Reality

Does the denial of the validity of these proofs mean we can say nothing about God? In ontology, God is often presented as a theory explaining the existence of all reality—a problem science does not address. The fundamental question is: Why is there something rather than nothing?

This wonder forces a dilemma between two ontological positions:

• Reality exists by itself (auto-sufficient).
• Reality depends on another reality.

God is often called the self-sufficient ground, the principle of existence. This dilemma compels us to admit either that all reality is God or that God exists separately from the fact of existence we observe.

Philosophy, for the moment, cannot proceed much further. From the fact of reality's existence—the decisive event—we must admit a necessity for an existence that asserts itself and cannot derive from nothingness. Little can be said about the ultimate grounding of this reality. Religious traditions are responsible for further claims. Natural theology must remain very humble.

First Philosophy

Starting Points in Knowledge

For philosophers, real people given in sense experience are the starting point of all knowledge. Idealists argue the starting point must be consciousness, as we know it exists. The ontological argument posits that reality can only be known through God, believing everything in God reveals Him most immediately.

Thomas Aquinas believed that the existence of all beings was a participation in God's existence, meaning God is inherently present in the knowledge of all things.