Existence of God


There is no other question as important as “Does God exist?” If He does not, then we must concede that there is ultimately nothing special about the world and the beings that inhabit it. Mankind is merely the product of a random and senseless cosmic process that will, eventually, swallow us in death both personally and as a species.

On the other hand, if God does exist, then the universe and the beings that inhabit it do have ultimate meaning and purpose, and death does not have the final word. One thing is certain: God’s existence is no trivial question.

Given the limited space of a pamphlet, we will only be able to scratch the surface of these arguments. Many in-depth resources, however, can be found at the SPSE website (see the link below). Whether you are an atheist, an agnostic or a believer, it’s my hope that this pamphlet will help you find answers concerning God’s existence. After all, it’s no small question.

1. The Kalaam Argument

The Kalaam argument is based on the idea that the universe began to exist and thus has a cause. The core idea can be phrased as follows:

1.      Whatever begins to exist has a cause for its existence.

2.      The universe began to exist.

3.      Therefore, the universe was caused by something else.

Number 1 seems obviously true, by our experience. Things do not simply pop into existence, uncaused, out of nothing. Indeed, if anything did appear to simply pop into existence, we would immediately begin asking why: what the cause of it was.

What about number 2? Did the universe, all of time, space, matter, and energy, begin to exist? Though historically some have believed that the universe is eternal and uncaused, recent scientific discoveries suggest otherwise. According to the standard view (in physics and astronomy) of how the universe began, it sprang into existence around 13.7 billion years ago in an event called “the Big Bang.” This is commonly viewed as an actual first event, not preceded by anything else. Indeed, space and time themselves are held to have come into existence with the Big Bang.

According to this model, asking “What happened before the Big Bang?” is a nonsensical question. Nothing can come before the first event. It is like asking “What’s north of the North Pole?” If nothing can begin to exist without a cause and the universe began to exist, then it follows that there is a cause of the universe.

What can we know about this cause? Because it created space and time it must transcend space and time. Because it created matter, it must be immaterial (by the principle of “the stream can’t rise higher than its source”). Furthermore, it (or we should say, “He”) must be personal.  Philosopher William Lane Craig argues why this must be so: “How else could a timeless cause give rise to a temporal effect like the universe? If the cause were an impersonal set of necessary and sufficient conditions, then the cause could never exist without the effect. … The only way for the cause to be timeless and the effect to begin in time is for the cause to be a personal agent who freely chooses to create an effect in time without any prior determining conditions.” (Craig, William Lane, Antony Flew, and Stan W. Wallace, Does God exist?: the Craig-Flew debate (Aldershot, Hants, England: Ashgate, 2003), 20.)

This argument is not intended to prove all of the attributes of God. But if this argument is sound, it does give us a beginningless, uncaused, timeless, immaterial, enormously powerful, transcendent, Personal Creator of the universe. That sounds a lot like God.

2. The Contingency Argument

This argument can be briefly stated as follows:

  1. Whatever could be different than it is requires an explanation.
  2. The physical universe could be different than it is.
  3. Therefore, the universe requires an explanation.

Number 1 represents the fundamental human perception that there are reasons for the things we see around us. This is what drives science, as well as every other branch of study. It is the great question: “Why?”

This question applies to anything that could be different than it is (what philosophers sometimes refer to as “contingent” things, that is, things that are one way but could have been another way). When we think about something — anything — and realize that it could be different, we naturally ask why it isn’t different. We seek an explanation for the way it is. If we see a one-armed person, then we wonder why he doesn’t have two arms. Perhaps it was an accident. Perhaps it was a birth defect. In any event, something caused it.

We can turn the question around and ask why a two-armed person has two arms. This is the normal situation for humans, but there is still a reason for it, which medical science has investigated. To say that there isn’t an explanation for why a person has the number of arms he does—not that we don’t know the reason but that there actually isn’t one—strikes at the foundation of rational thought. It is to reject the whole premise that underlies the quest for knowledge. The first premise of our argument (number 1) thus seems secure.

Number 2 is also. If we look about the physical universe, we see it filled with stars and galaxies, and we see that the phenomena within it obey certain laws. Gravity is a certain strength and not stronger or weaker. Light travels at a particular (unchanging) speed and not faster or slower. The universe also contains a certain amount of matter and energy, not more or less. Why?

All of this could be different. At one time the universe did not contain stars and galaxies. What was it like before? How many dimensions of space and time are there? Why do we experience three dimensions of space and one of time, not more or less? Why is gravity precisely as strong as it is? Why does light move at the speed it does and not another?

All of these matters are subjects of scientific inquiry, and they reveal that the physical universe as a whole is contingent. That is, the universe is one way but could have been another. It therefore needs a reason for the way it is—an explanation.

But let’s inquire a bit further and ask about what could explain the way the physical universe is as it is. The explanation for it must lie beyond the physical universe itself. It must be something beyond space and time, beyond matter and energy, but with the power to create each of these and to establish the laws that they obey. Once again, that sounds a lot like God.

You might ask whether God Himself requires a further explanation. The answer in this case is no, because unlike the physical universe, God is not a contingent Being. He could not fail to exist or have different attributes than He does. This is why Christian philosophers and theologians say that God is a necessary Being, one that does not have the kind of contingency that characterizes the physical universe and all the things in it. God could not be other than He is. He simply is.

This is something our intuition also tells us: there must be an ultimate explanation: one that does not depend on anything else, and thus one that explains everything else. Something fundamental, that grounds all the contingent things we see around us, is required. Thus, there must be a God.

3. The Moral Argument

The Moral Argument can be phrased like this:

  1. If God does not exist, then objective moral values do not exist.
  2. Objective moral values do exist.
  3. Therefore, God exists.

Christians and atheists may (and often do) agree with number 1. Many Christians have argued that if God did not exist then there would not be a rational basis for objective morality. Similarly, many atheists have said that morality is merely a human (and therefore, subjective and relative) construct and that it does not have objective existence.

For example, the atheist philosopher Michael Ruse has argued that morality “is a biological adaptation no less than are hands and feet and teeth.” Consequently, he has said that “considered as a rationally justifiable set of claims about an objective something, [morality] is illusory. I appreciate that when somebody says, ‘Love thy neighbor as thyself,’ they think they are referring above and beyond themselves,” but he concludes that “such reference is truly without foundation. Morality is just an aid to survival and reproduction,” and consequently, “any deeper meaning is illusory”. (Michael Ruse, “Evolutionary Theory and Christian Ethics,” in The Darwinian Paradigm (London: Routledge, 1989), pp. 262, 268-269).

However, if we’re honest, we must acknowledge number 2 instead. When we hear stories of mass murders or genocides in distant lands, we do not think, “These make no difference. It is perfectly fine to kill innocent people. Their lives are without any objective meaning.” We recognize, instead, that people do matter and that we cannot treat them like unimportant, disposable objects. It is objectively wrong to kill innocent people, and to deny this is to deny a fundamental perception of the human heart. It is, in fact, inhuman to propose this.

The intuition that moral values are real is so deeply embedded in the human heart that even those who deny objective morality invariably slip back into moralizing. Even a brief survey of the writings of prominent atheists reveal a constant drumbeat of moral judgments and, indeed, moral outrage. The question is not whether moral values objectively exist, but what their basis can be. Here are four possibilities:

Nature: In this case, morals would be something that exist objectively in nature. But we can’t measure good and evil in a scientific experiment. Therefore, if they exist, they transcend the realm of science and point to a realm that is beyond the merely natural.

Individual Choice: Some have suggested that we make our own morality — that it arises from our individual choice. While this could explain morality as a subjective phenomenon, it does nothing to explain why things are objectively right and wrong. It also would not result in a set of moral values that are binding. If I have the authority to bind myself, I also have the authority to unbind myself.

Society: Perhaps moral values are established by society. This is simply a collective version of the individual choice idea, where the choices of a whole group of individuals are held to be the basis of morality. As a result, it again does not establish an objective, binding morality. What right do others have to tell me what I should and should not do?

God: Finally, objective morality may be grounded in God—in His own nature and goodness. Only if morality originates in something above me would it have authority over me. Thus, without God there is no objective basis for morality. Of course, this does not mean that atheists cannot act morally nor is it arguing that something is good simply because God commands it. It does mean, however, that there is something that transcends the natural order—God Himself—that serves as the basis of morality.


If you are an atheist, the fact you have taken the time to read this pamphlet is a sign that you are open to the possibility of God’s existence. I would encourage you to check out the resource section at streetevangelization.com for thoughtful answers to your honest questions.

Written By: Matt Fradd

After experiencing a profound conversion at World Youth Day in Rome in 2000, Matt Fradd committed himself to inviting others to know Jesus Christ and the Church He founded. Matt has been a missionary in Canada and Ireland, proclaiming the Gospel to over ten thousand teens and young adults, and has been a guest on the BBC, EWTN, ABC and Catholic Answers Live. Matt currently lives (and surfs) in Southern California with his wife and three children where he currently works as an Apologist and Speaker with Catholic Answers. Learn more about Matt by visiting mattfradd.com.

Edited By: Dave Armstrong

Bible Version: Revised Standard Version

Copyright and Permissions


Further Reading: 



Catholic Answers Live podcasts




Debate: William Lane Craig vs. Christopher Hitchens.

Info on Philosophy, Science, and Christianity

Atheism, Agnosticism, and Secularism



Catechism of the Catholic Church

Compendium of the Catechism of the Catholic Church

Handbook of Catholic Apologetics, by Peter J. Kreeft and Ronald K. Tacelli

The Essential Catholic Survival Guide, by Catholic Answers

Pope John Paul II’s encyclical Fides et Ratio (“Faith and Reason”)

Christian Worldview vs. Postmodernism

Science and Christianity: Close Partners or Mortal Enemies

Printed With Ecclesiastical Permission. Most Reverend Earl Boyea. August 13, 2013.

Catholic Tracts