Does God exist? This is one of the most important questions a person can consider. Your belief in the existence of God has enormous implications on your views of life, humanity, morality, and destiny. In this article, Dr. Craig offers three reasons why life would be meaningless without God and then presents five strong arguments for the existence of God, demonstrating the reasonableness of believing that God exists.
Does God exist? Here are five good reasons to think that God exists:
God makes sense of the origin of the universe.
God makes sense of the fine-tuning of the universe for intelligent life.
God makes sense of objective moral values in the world.
God makes sense of the life, death, and resurrection of Jesus.
God can be immediately known and experienced.
Does God exist? C. S. Lewis once remarked that God is not the sort of thing one can be moderately interested in.
After all, if God does not exist, there's no reason to be interested in God at all.
On the other hand, if God does exist, then this is of paramount interest, and our ultimate concern ought to be how to be properly related to this being upon whom we depend moment by moment for our very existence.
So people who shrug their shoulders and say, "Does God exist? What difference does it make?" merely show that they haven't yet thought very deeply about this problem. Even atheist philosophers like Sartre and Camus—who have thought very seriously about this problem—admit that the existence of God makes a tremendous difference for man.
Let me mention just three reasons why it makes a big difference whether God exists.
Three reasons why His existence makes a difference
Reason 1: Life is Ultimately Meaningless Without God
If God does not exist, life is ultimately meaningless. If your life is doomed to end in death, then ultimately it does not matter how you live. In the end it makes no ultimate difference whether you existed or not.
Sure, your life might have a relative significance in that you influenced others or affected the course of history. But ultimately mankind is doomed to perish in the heat death of the universe. Ultimately it makes no difference who you are or what you do. Your life is inconsequential.
Thus, the contributions of the scientist to the advance of human knowledge, the research of the doctor to alleviate pain and suffering, the efforts of the diplomat to secure peace in the world, the sacrifices of good people everywhere to better the lot of the human race—ultimately all these come to nothing.
Thus, if atheism is true, life is ultimately meaningless.
Reason 2: Without God We Live Without Hope
If God does not exist, then we must ultimately live without hope. If there is no God, then there is ultimately no hope for deliverance from the shortcomings of our finite existence.
For example, there is no hope for deliverance from evil. Although many people ask how God could create a world involving so much evil, by far most of the suffering in the world is due to man's own inhumanity to man. The horror of two world wars during the last century effectively destroyed the 19th century's naive optimism about human progress.
If God does not exist, then we are locked without hope in a world filled with gratuitous and unredeemed suffering, and there is no hope for deliverance from evil.
Or again, if there is no God, there is no hope of deliverance from aging, disease, and death. Although it may be hard for you as university students to contemplate, the sober fact is that unless you die young, someday you—you yourself—will be an old man or an old woman, fighting a losing battle with aging, struggling against the inevitable advance of deterioration, disease, perhaps senility. And finally and inevitably you will die. There is no afterlife beyond the grave. Atheism is thus a philosophy without hope.
Reason 3: If God Exists, You Can Know His Love Personally
On the other hand, if God does exist, then not only is there meaning and hope, but there is also the possibility of coming to know God and His love personally.
Think of it!
That the infinite God should love you and want to be your personal friend! This would be the highest status a human being could enjoy!
Clearly, if God exists, it makes not only a tremendous difference for mankind in general, but it could make a life-changing difference for you as well.
Now admittedly none of this shows that God exists. But it does show that it makes a tremendous difference whether God exists. Therefore, even if the evidence for and against the existence of God were absolutely equal, the rational thing to do, I think, is to believe in Him. That is to say, it seems to me positively irrational when the evidence is equal to prefer death, futility, and despair over hope, meaningfulness and happiness.
But, in fact, I don't think the evidence is absolutely equal. I think there are good reasons to believe in God. And today I want to share briefly five of those reasons. Whole books have been written on each of these, so all I have time to do is to present a brief sketch of each argument and then during the discussion time we can go more deeply into any of them that you'd like to talk about.
Does God exist? As travelers along life's way, it's our goal to make sense of things, to try to understand the way the world is. The hypothesis that God exists makes sense out of a wide range of the facts of experience.
God makes sense of the origin of the universe
Have you ever asked yourself where the universe came from? Why everything exists instead of just nothing? Typically atheists have said the universe is just eternal, and that's all.
But surely this is unreasonable. Just think about it a minute. If the universe never had a beginning, that means that the number of past events in the history of the universe is infinite. But mathematicians recognize that the existence of an actually infinite number of things leads to self-contradictions.
For example, what is infinity minus infinity? Well, mathematically, you get self-contradictory answers. This shows that infinity is just an idea in your mind, not something that exists in reality. David Hilbert, perhaps the greatest mathematician of the twentieth century, states, the infinite is nowhere to be found in reality. It neither exists in nature nor provides a legitimate basis for rational thought. The role that remains for the infinite to play is solely that of an idea.
But that entails that since past events are not just ideas, but are real, the number of past events must be finite. Therefore, the series of past events can't go back forever; rather the universe must have begun to exist.
This conclusion has been confirmed by remarkable discoveries in astronomy and astrophysics.
In one of the most startling developments of modern science, we now have pretty strong evidence that the universe is not eternal in the past but had an absolute beginning about 13 billion years ago in a cataclysmic event known as the Big Bang. What makes the Big Bang so startling is that it represents the origin of the universe from literally nothing. For all matter and energy, even physical space and time themselves, came into being at the Big Bang.
As the physicist P. C. W. Davies explains, "the coming into being of the universe, as discussed in modern science . . . is not just a matter of imposing some sort of organization . . . upon a previous incoherent state, but literally the coming-into-being of all physical things from nothing."
Of course, alternative theories have been crafted over the years to try to avoid this absolute beginning, but none of these theories has commended itself to the scientific community as more plausible than the Big Bang theory.
In fact, in 2003 Arvind Borde, Alan Guth, and Alexander Vilenkin were able to prove that any universe which is, on average, in a state of cosmic expansion cannot be eternal in the past but must have an absolute beginning. Vilenkin pulls no punches:
It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape, they have to face the problem of a cosmic beginning.
That problem was nicely captured by Anthony Kenny of Oxford University. He writes, "A proponent of the Big Bang theory, at least if he is an atheist, must believe that the universe came from nothing and by nothing."
But surely that doesn't make sense!
Out of nothing, nothing comes. So why does the universe exist instead of just nothing? Where did it come from? There must have been a cause which brought the universe into being.
We can summarize our argument thus far as follows:
Whatever begins to exist has a cause.
The universe began to exist.
Therefore, the universe has a cause.
Given the truth of the two premises, the conclusion necessarily follows.
From the very nature of the case, this cause must be an uncaused, changeless, timeless, and immaterial being which created the universe. It must be uncaused because we've seen that there cannot be an infinite regress of causes. It must be timeless and therefore changeless—at least without the universe—because it created time. Because it also created space, it must transcend space as well and therefore be immaterial, not physical.
Moreover, I would argue, it must also be personal. For how else could a timeless cause give rise to a temporal effect like the universe? If the cause were a mechanically operating set of necessary and sufficient conditions, then the cause could never exist without the effect.
For example, the cause of water's freezing is the temperature's being below 0˚ Centigrade. If the temperature were below 0˚ from eternity past, then any water that was around would be frozen from eternity. It would be impossible for the water to begin to freeze just a finite time ago. So if the cause is permanently present, then the effect should be permanently present as well. 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.
For example, a man sitting from eternity could freely will to stand up. Thus, we are brought, not merely to a transcendent cause of the universe, but to its personal Creator. Isn't it incredible that the big bang theory thus confirms what the Christian theist has always believed: that in the beginning God created the universe? Now I put it to you: which makes more sense: that the Christian theist is right or that the universe popped into being uncaused out of nothing? I, at least, have no trouble assessing these alternatives!
God makes sense of the fine-tuning of the universe for intelligent life.
During the last 40 years or so, scientists have discovered that the existence of intelligent life depends upon a complex and delicate balance of initial conditions given in the Big Bang itself. Scientists once believed that whatever the initial conditions of the universe, eventually intelligent life might evolve. But we now know that our existence is balanced on a knife's edge. The existence of intelligent life depends upon a conspiracy of initial conditions which must be fine-tuned to a degree that is literally incomprehensible and incalculable.
This fine-tuning is of two sorts.
First, when the laws of nature are expressed as mathematical equations, you find appearing in them certain constants, like the gravitational constant. These constants are not determined by the laws of nature. The laws of nature are consistent with a wide range of values for these constants.
Second, in addition to these constants there are certain arbitrary quantities which are just put in as initial conditions on which the laws of nature operate, for example, the amount of entropy or the balance between matter and anti-matter in the universe. Now all of these constants and quantities fall into an extraordinarily narrow range of life-permitting values. Were these constants or quantities to be altered by a hair's breadth, the life-permitting balance would be destroyed and life would not exist.
For example, the physicist P. C. W. Davies has calculated that a change in the strength of gravity or of the atomic weak force by only one part in 10100 would have prevented a life-permitting universe. The cosmological constant which drives the inflation of the universe and is responsible for the recently discovered acceleration of the universe's expansion is inexplicably fine-tuned to around one part in 10120.
Roger Penrose of Oxford University has calculated that the odds of the Big Bang's low entropy condition existing by chance are on the order of one out of 10 10 (123). Penrose comments, "I cannot even recall seeing anything else in physics whose accuracy is known to approach, even remotely, a figure like one part in 1010 (123)."  And it's not just each constant or quantity which must be exquisitely finely-tuned; their ratios to one another must be also finely-tuned. So improbability is multiplied by improbability by improbability until our minds are reeling in incomprehensible numbers.
Now there are three possibilities for explaining the presence of this remarkable fine-tuning of the universe: physical necessity, chance, or design.
The first alternative holds that there is some unknown Theory of Everything (T.O.E.) which would explain the way the universe is. It had to be that way, and there was really no chance or little chance of the universe's not being life-permitting.
By contrast, the second alternative states that the fine-tuning is due entirely to chance. It's just an accident that the universe is life-permitting, and we're the lucky beneficiaries. The third alternative rejects both of these accounts in favor of an intelligent Mind behind the cosmos, who designed the universe to permit life.
Which of these alternatives is the most plausible?
The first alternative seems extraordinarily implausible. There is just no physical reason why these constants and quantities should have the values they do. As P. C. W. Davies states, Even if the laws of physics were unique, it doesn't follow that the physical universe itself is unique. . . . the laws of physics must be augmented by cosmic initial conditions. . . . There is nothing in present ideas about 'laws of initial conditions' remotely to suggest that their consistency with the laws of physics would imply uniqueness. Far from it. . . . . . . it seems, then, that the physical universe does not have to be the way it is: it could have been otherwise.
For example, the most promising candidate for a T.O.E. to date, super-string theory or M-Theory, fails to predict uniquely our universe.
In fact, string theory allows a "cosmic landscape" of around 10500 different universes governed by the present laws of nature, so that it does nothing to render the observed values of the constants and quantities physically necessary.
So what about the second alternative, that the fine-tuning of the universe is due to chance? The problem with this alternative is that the odds against the universe's being life-permitting are so incomprehensibly great that they cannot be reasonably faced. Even though there will be a huge number of life-permitting universes lying within the cosmic landscape, nevertheless the number of life-permitting worlds will be unfathomably tiny compared to the entire landscape, so that the existence of a life-permitting universe is fantastically improbable.
Students or laymen who blithely assert, "It could have happened by chance!" simply have no conception of the fantastic precision of the fine-tuning requisite for life. They would never embrace such a hypothesis in any other area of their lives—for example, in order to explain how there came to be overnight a car in one's driveway.