What is classical theism? For one, it’s a notion all too commonly ignored. Catholic Philosopher Dr. Edward Feser writes:

I have often complained that it is not just New Atheist types, but too many contemporary Christian thinkers, who are operating with a seriously deficient conception of God and a seriously deficient set of background metaphysical assumptions. (source)

Additionally, as Thomas M. Cothran writes:

Classical theism refers very generally to the way most of the great theological and philosophical traditions have conceived God: as the cause of all finite being, the ground of the good, eternal, immutable, transcendent of space and time, perfect, omnipotent, immaterial, infinite, and omniscient. (source)

How Do We Show God Exists?

While evidence for the existence of God abounds, not all arguments for God are created equal. Some are best viewed as signposts while others purport to be metaphysical demonstrations.

Much of popular contemporary apologetics makes use of signposts, inferences to the best explanation, and cumulative case arguments. For examples of these arguments, I suggest the following works (currently on my shelf):

• On Guard by William Lange Craig
• I Don’t Have Enough Faith to Be an Atheist by Frank Turek
• Evidence for God by William Dembski and Michael Licona

These pieces of evidence for God are typically probabilistic and reveal only a thin slice of the Divine nature. As a result, they are open to common objections:

• The conclusion of the argument may not be God since it does not have a lot of the traditional attributes associated with God.
• Perhaps there are many Gods (polytheism) or an uninvolved God (deism), which explain the phenomena under consideration.
• Your argument uses God to plug up a current gap in our understanding. One day, science will explain your point away in purely natural terms.

This is not to say we should jettison signpost arguments. I find them to be extremely useful tools in evangelism. Grace builds upon nature, and God works to draw different people in different ways. Some find signpost arguments persuasive and thereby gain confidence in their faith. Here, I want to stress that these arguments are not the only game in town.

What Else is There?

As indicated above, there are also metaphysical demonstrations for God’s existence. These demonstrations proceed from philosophical premises and data from common experience, not from weird or kooky phenomena.

Moreover, these arguments lead to the God of classical theism, rather than simply hinting at the probability of an ambiguous supernatural entity. They conclude to a God who is pure actuality, absolutely simple, one, immutable, eternal, and self-existent. They bring us to a God with intellect and will who is omnipotent, omniscient, and good.

Polytheism or deism fail to remain a live option on principled grounds. These arguments reach the God of the philosophers whom Aristotle, Plotinus, Augustine, Avicenna, Maimonides, Aquinas, Leibniz, and others showed could be reached by natural reason. Throughout the ages, Jewish, Christian, and Muslim philosophers have grasped the existence of this God.

This is the God of classical theism. At the First Vatican Council, the Catholic Church restated its commitment to this view:

The Holy Catholic Apostolic Roman Church believes and confesses that there is one true and living God, Creator and Lord of heaven and earth, Almighty, Eternal, Immense, Incomprehensible, Infinite in intelligence, in will, and in all perfection, who, as being one, sole, absolutely simple and immutable spiritual substance, is to be declared as really and essentially distinct from the world, of supreme beatitude in and from Himself, and ineffably exalted above all things which exist, or are conceivable, except Himself. (source)

What is a Metaphysical Demonstration?

First of all, Metaphysical demonstrations involve metaphysics i.e. the study of being and things that exist. Now, metaphysics does not consist of scientific examinations of physical phenomena. Rather, it is a philosophical discipline analyzing reality at a deeper level. It seeks to determine what must be true about things and reality independent of whatever the facts of chemistry, biology, and physics turn out to be.

That’s the first point: metaphysical demonstrations involve metaphysical premises.

Second, they are demonstrations in the sense that the premises follow from one another with deductive validity. Think back to proofs in high school geometry. Each step requires justification. Prior premises entail the truth of later premises.

Moreover, since metaphysical demonstrations rest on philosophical premises that are more secure than scientific models and theories, they come with metaphysical certainty. In other words, as ambitious as this sounds, metaphysical demonstrations of God’s existence amount to proofs that God exists. They are proofs in the sense that the premises entail the conclusion in a manner more secure than results obtained in the laboratory.

This is a big deal. Hence, more people need to know the arguments that lead to the God of Classical Theism. What are these arguments? Well, if you want to dive right in, the book for you is Five Proofs of the Existence of God by Dr. Edward Feser.

In part 2 of this series, we examine one of these metaphysical demonstrations.