Theistic Arguments and the Necessity of God

There are many different types of necessity.

Logical Necessity and the Ontological Argument

A logically necessary entity exists in every possible world. (A “possible world” is just a logically possible state of affairs.) That is, there is no logically possible state of affairs in which a logically necessary entity does not exist.

The ontological argument seeks to demonstrate, among other things, that God is a logically necessary entity. Since God is the greatest possible being, there is no logically possible state of affairs in which God does not exist. It is greater for God to exist in every possible world than it is for God to not exist in at least one possible world, and since God is the greatest possible being, God exists in every possible world.

Metaphysical Necessity and the Cosmological Argument

A metaphysically necessary entity exists in the actual world which is, in some sense, contingent upon it. (The “actual world” is not merely a logically possible state of affairs, but the state of affairs in which we actually find ourselves.) That is, there is no metaphysically possible state of affairs in which a metaphysically necessary entity does not exist.

The cosmological argument seeks to demonstrate, among other things, that God is a metaphysically necessary entity. Since God is the first cause, there is no metaphysically possible state of affairs in which God does not exist. If there are causes in the actual world, then there must be a first cause. There are causes in the world, thus there is a first cause. God exists in the actual world.

Transcendental Necessity and the Transcendental Argument

A transcendentally necessary entity exists in every possible world in which there is rational experience. The actual world happens to be one in which there is rational experience. That is, there is no rational experience where a transcendentally necessary entity does not exist.

The transcendental argument seeks to demonstrate, among other things, that God is a transcendentally necessary entity. Since a denial of the existence of God as a logically and metaphysically necessary being leads to a denial of rational experience, it follows from rational experience that God exists.

Though sloppily stated, the claims above provide a place to begin to study the different types of necessity and different types of arguments for the necessary being who is the God of the Bible.