Can Human Reason Lead Us to
Believe in the Existence of God?

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  1. First Proof: Is the world designed by Chance?
  2. The Second Proof: The First Cause of all Creation!
  3. The Third Proof: Our Conscience!
  4. The Fourth Proof: History!
  5. The Fifth Proof: Pascal's Wager!
  6. Summary.

The purpose of this leaflet is to summarize five philosophical proofs that have been derived from human reason, for the existence of God. It is hoped that these proofs will enhance the faith of those who know God and worship him in their lives. It is also hoped that these same proofs will help those of us who are still searching.

How, in fact, do we know anything? How do we know that when we drop a stone it will fall to the ground and not fly up and hit us in the face? The answer is simple, we know it from lifelong personal experience. If for some strange reason we had not yet had the personal experience of seeing a stone drop, we could still believe that it does from the study of physics and Newton's laws of gravity. Even for those of us who had seen a stone drop, the study of these laws would enhance, strengthen and deepen our knowledge and allow us to more fully appreciate the reality of a dropping stone.

Our knowledge of God is similar. The deepest knowledge of God and of the certainty of His existence comes through the personal experience of Him in our lives. What we will try to show, in the sections that follow, is a summary of the ways in which reason can help us also, to appreciate the reality of God.

First Proof: Is the world designed by Chance?

There are two possible ways to describe the world. The first way is that it follows the design of a supreme intelligence while the second way says that it came to be what it is strictly by chance.

No rational person seriously believes that great art such as Michelangelo's David or Beethoven's symphonies arises as the result of a random series of hammer blows or a randomly produced sequence of notes. We simply know from experience that these beautiful creations are the result of an artist and could never come into being randomly or by chance.

Both the universe and human intelligence, are far more complex and more beautiful than either of these examples of art and music, so it is only reasonable to expect, based on the simple experience of our lives, that they must have had a supremely intelligent designer or God. So if a person does not believe in a God as a creator, that person has to then believe that the scientific laws governing the universe and also our intelligence are only the result of a chance occurrence. The probability of such a random occurrence actually happening is so infinitely small as to defy all reason.

The Second Proof: The First Cause of all Creation!

We all know that in real life everything that exists has a cause. We were born because of our parents, as they in turn were born because of theirs, and so on back to our first parents. The thought that something occurs without a cause is not seriously accepted by anyone. When a child comes home with a black eye we know and believe that there had to be a cause for it and we will not accept an explanation that"it just happened". When we apply the same reasoning to the universe we can see that like the black eye, it did not just happen but had a cause and that first cause was God.

Each individual event in the universe arises from a previous event. The stream of events either had a beginning or they did not. All logic points to a beginning event and that event was caused by God. The first proof dealt with the design of nature as described by its laws, such as those which govern the falling stone, and perceived by our senses. The second proof shows us how the whole wonderful design of nature was set in motion. It shows us how the falling stone of the first proof was formed in the first place and then, in the illustration we are using, set on its falling journey.

The Third Proof: Our Conscience!

We all know, from what we call our conscience, that it is right to do good and wrong to do evil and we sense that we have an obligation to act according to the ordering of our conscience. Even in a materialistic and humanistic society almost all people, Christian or not, believe that a person should follow the dictates of their conscience. Those few people who do not have this awareness of conscience are considered by this same society to be mentally ill.

This conscience is not just a feeling within us but extends to our human intellect being applied to the knowledge base that we have acquired during our lives. Conscience not only tells us what we should do but sets before us an obligation that we are required to carry out if we are to remain at peace with ourselves. Conscience is the voice of God speaking to our souls.

However, if God does not exist and we are only here by chance, so that there is no meaning to our existence, what obligation can there be to follow our conscience or anything else. Our sense of obligation towards doing good is only logical if there is a fundamental morality that transcends human existence and which has the power and right to demand moral obedience.

The Fourth Proof: History!

The people who knew Christ best were his disciples and their immediate descendants who formed the early church. They were so convinced by the truth of the Christian teaching that they had received that they were willing to accept the vilest persecutions in witness to their faith.

Most of the apostles and their immediate disciples were martyred, including St. Paul. The Roman persecutions of the early Christians led to over one hundred thousand of them choosing a martyrs death as a witness to their faith in God rather than to deny their conscience in order to escape these persecutions.

The first thirty one bishops of Rome from St. Peter down to St. Eusebius who died in 309 A.D., all died for their faith in Christ. This heroic witness to the faith of believers has continued down through the centuries. In more recent time this has included persecutions by the Nazi and Communist regimes under whose cruel authority tens of thousands died for their faith. Even in the present day the bloody martyring of Christians goes on in parts of Africa and Latin America.

For almost 2,000 years countless people have lead joyful and often heroic lives firm in their belief in God. Were all these people deluded or insane? Or were they right?

The Fifth Proof: Pascal's Wager!

Pascal was a seventeenth century philosopher, scientist and mathematician who argued the existence of God in terms of a wager. He based his wager on the fact that a normal, rational man will, when given two possible choices, choose the one with the best chance of obtaining a reward.

For instance, if someone says that your house is on fire, it could be or it could not. The cost of finding out if it is, such as looking to see if it is, is small compared to the potential loss of not bothering to look and finding it burnt down. It would be utter foolishness for you not to take that look to see if your house is on fire.

In the same manner, we are all forced to face the fact that one day we are going to die. At that moment of our death we will be faced with the fact that either God exists or He doesn't. If He doesn't exist, then it will not matter whether or not we had thrown our lot in with God during our lives. If on the other hand though, God does exist and we were faithful to Him, we will receive an infinite reward. In the same way, if he does exist and we were unfaithful during our lifetime, we lose everything.

So if we bet that God exists and we were right we win everything. In the same way, if we bet that God exists and we are wrong and he does not exist, we have lost nothing.

If we now look at it from the other side and at the start of our lives bet that God does not exist and are right then we win nothing. In the same way, if we bet that God does not exist and are wrong then we lose everything. So the only sensible wager is the bet that God exists. With such a wager we have everything to gain and nothing to lose.


If we accept the fact that God exists and that he created the universe and man with a conscience and a free will, to choose from right or wrong, it is unreasonable to expect that having created us he would not want to communicate with us and show us his desires for us.

Over the millennia this communication has taken place within our conscience, other early religions, Judaism and ultimately His Son Incarnate, Jesus Christ. The communication through Christ is revealed to us in the scriptures and through tradition and is interpreted by the teaching authority of the Roman Catholic Church.

How then do we move from intellectual assent to a personal knowledge of God? Our relationship with God moves through stages. The first is when we seek him. Once we seek Him we already have found Him. Next we get to know Him through study, prayer and the church. Finally, through faithfulness, prayer and meditation our relationship turns to one of love.

If you would like to learn more about God and the Roman Catholic faith you are invited to simply phone the rectory of the Catholic Church nearest to you and ask to speak to the Pastor. If he is unavailable, explain to the person who answers the phone that you are interested in finding out more about the Catholic Church and they should be able to help you.

We have another leaflet that you might find helpful called "Approaching the Catholic Church for the First Time." We would be happy to send it to you by mail or you can read it on our Internet web site, both addresses are on the back of this leaflet.

W. Craig

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