Many proofs for the existence of God have been formulated, and it can be difficult for the amateur apologist to understand and commit each to memory.  Dr. Kreeft, in his Summa of the Summa, lays out 24 arguments, and admits that there are many more!  Beyond this, the differences between each argument can be subtle (yet substantial).  The difference between the Argument from Motion and the Argument from Efficient Causation can be puzzling as each proves the existence of God in a slightly different way.  Let me suggest focusing on a few “major” arguments to begin building one’s toolkit.

Each argument belongs to a certain “type”—cosmological, psychological, etc.–and this is important because the people we speak with all have different types of evidence that is most persuasive to them.  Me?  Lay out a few logic-centric philosophical arguments, and you’ll have me immediately probing to find holes—if I can’t, I’m persuaded.  Yet, others will look at a socratic argument and briskly walk away.  The goal of the amateur apologist is to listen to their interlocutor and try to discern what type of evidence will be most persuasive.  I intend to lay out four arguments for the existence of God, two in this post that are of the more rigorously philosophical type, and an additional two arguments in a later post that are of the more experiential type.  When defending the faith, don’t just rattle off arguments at random.  Listen to your interlocutor, and decide what is best for them.  Don’t try to reason with Bacchus, nor revel with Apollo!

Teleological Argument:  Argument from Design

St. Thomas Fifth Way, the Argument from Design, is often misunderstood in modern literature which tries to equate it to William Paley’s “Watchmaker” argument.  Let’s be clear that this argument is NOT about biology or irreducible complexity, but around the regularity of nature.  In our everyday lives, it’s clear that most everything exhibits a normal, recognizable pattern.  Think about this!  Adding heat to water causes it to boil (adding heat never causes the water to turn into aluminium).  Planting flowers in healthy soil causes them to grow and blossom (it never causes them to become a puppy).  These are playful examples, but they illustrate the key premise of this argument—everything in nature, even mindless materials like heat, water, soil, and flowers, exhibit some level of directedness, or purpose.  This is such a common occurrence for us that we lose sight of this amazing fact.  The basic argument says, for nature to exhibit a directedness towards an end, there must be an intelligence that directs it.  Now, the common retort is that the laws of nature cause this apparent directedness.  However, that only pushes the argument backward one level, for why do the laws of nature always act in a predictable manner.  What causes them to always hold true?  The only explanation for why the whole of nature and many things in it have such predictable patterns is that an intelligence directs these things towards their ends.

Cosmological Argument:  Kalam Argument

The most useful aspect of this argument is its accessibility to commonsense.  It reads like this:

Whatever begins to exist must have a cause.
The universe began to exist.
Therefore, the universe has a cause.

The premises themselves are difficult to deny, an appeal to common experience leads us to evidence for the first premise.  Electricity causes your light bulb to shine.  The painter causes the masterpiece through his talent and materials.  Chairs are caused by the chairmaker.    Ask yourself the question, “Can I think of any example of something coming into being without a cause?”  No?  Then the first premise is extremely likely as supported by common experience.

Regarding the second premise, we have the support of cosmology.  Ever heard of the Big Bang?  Of course you have!  It’s the moment of the creation of our universe.  This leading scientific theory provides strong evidence for the second premise put forth by the Kalam argument.

So the first premise confirmed by common experience coupled with the second premise confirmed by the efforts of modern science lead us inexorably to the conclusion that “The universe has a cause!”  “What then,” you may be asking, “does that have to do with evidence for God?” Well, if the universe is the sum-total of everything that exists in our world—time and space included—then this cause must be transcendent to the universe, it must be immaterial.  The final key to the puzzle is found by asking the question of why the universe is only 13.7 billion years old.  If the cause of the universe—an immaterial substance—preceded the universe, then it is puzzling to explain why the universe hasn’t existed forever.  Only a mind with a will could choose to bring the universe into being at a precise time.  This mind with a will points to the existence of a personal God.

It’s important to understand the usefulness and scope of these arguments.  They do not take us all the way to proving the God of Christianity–that comes later.  They do however begin laying the foundation for Christian apologetics—the starting point for the conversations about the Fall, the historical Jesus, and other truths that are contingent upon a belief in a creator.


The opinions expressed by the DPS blog authors and those providing comments are theirs alone; they are not necessarily the expressions or beliefs of either the Dead Philosophers Society or Holy Apostles College & Seminary.