An excerpt from Dr. William Lane Craig's debate with an atheist.  Dr. Craig is a Christian philosopher, professor, avid speaker and author of books that validate Christianity. 

(Dr. Craig) In tonight's debate I'm going to be defending two basic contentions: First of all, that there's no good reason to think that atheism is true and, secondly, that there are good reasons to think that theism is true. 

I.  Atheism takes faith too.

So let's look at my first major contention together, that there are no good reasons to think that atheism is true. Atheism, or the claim that there is no God, is just as much a claim to know something as is theism, the claim that God does exist. Therefore, if the atheist is to prove his view, he must do more than say, "There's no good evidence for God's existence." He must present positive evidence against God's existence. Atheist philosophers have tried for centuries to disprove the existence of God, but no one has been able to come up with a convincing argument. So rather than attack straw men at this point, I'll just wait to hear Dr. Washington's answer to the following question: "What is the evidence that atheism is true?"

II.  There are good reasons to think that theism is true.

So let's turn, then, to my second basic contention, that there are good reasons to think that theism is true. Now I'm not claiming that I can prove that God exists with some sort of mathematical certainty. I'm certainly not going to be able to convince you against your will. I'm just saying that the evidence makes it plausible that God exists, that on balance theism is more probable than atheism. Let me present six reasons why I think it's plausible that God exists. We'll start with the most abstract and gradually get more concrete. 

The Argument from Abstract Objects 

1. God provides the best explanation for the existence of abstract entities. In addition to tangible, concrete objects like people and trees and chairs, philosophers have noticed that there also appear to be abstract objects, things like numbers, propositions, sets, and properties. These things have a sort of conceptual reality, rather like ideas in your mind. And yet it's obvious that they're not just ideas in any human mind. So what is the metaphysical foundation of such abstract entities? The theist has a plausible answer to that question. They are grounded in the mind of God. Alvin Plantinga, one of America's foremost philosophers, explains:

It seems plausible to think of numbers as dependent upon or even constituted by intellectual activity. But there are too many of them to arise as a result of human intellectual activity. We should therefore think of them as... the concepts of an unlimited mind: a divine mind.

At the most abstract level, then, theism provides a plausible, metaphysical foundation for the existence of abstract objects. And that's the first reason why I think it's plausible to believe in God.

The Cosmological Argument 

2. God provides the best explanation for why the universe exists instead of nothing.  Have you ever asked yourself where the universe came from, why anything at all exists, instead of just nothing? Well, typically atheists have said that the universe is eternal, and that's all. But surely this is unreasonable. Just think about it for a minute. If the universe never had a beginning, then that means that the number of past events is infinite. But mathematicians recognize that the idea 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 actually exists in reality.

David Hilbert, perhaps the greatest mathematician of this 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 in your mind 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 a series of remarkable discoveries in astronomy and astrophysics. The astrophysical evidence indicates the universe began to exist in a cataclysmic explosion known as the Big Bang 15 billion years ago. Physical space and time were created in that event, as well as all the matter and energy in the universe. Therefore, as the Cambridge astronomer Fred Hoyle points out, the Big Bang theory requires the creation of the universe from nothing. This is because, as you go back in time, you reach a point at which, in Hoyle's words, the universe was "shrunk down to nothing at all."  Thus, what the Big Bang model requires is that the universe began to exist and was created out of nothing.

No, this tends to be very awkward for the atheist. As Anthony Kenny of Oxford University says, "A proponent of the Big Bang theory, at least if he is an atheist, must believe that....the universe came by nothing and from nothing."  But that's a pretty hard pill to swallow! Out of nothing, nothing comes. So why does the universe exist? Where did it come from? There must have been a cause that brought the universe into being. From the very nature of the case, this cause must be an uncaused, changeless, timeless, and immaterial being which created the universe. Isn't it incredible that the Big Bang theory confirms what the Christian theist has always believed, that "In the beginning, God created the universe"?

Now I simply put it to you: which is more plausible?---That the Christian theist is right, or that the universe just popped into existence, uncaused, out of nothing? I, at least, don't have any trouble assessing these probabilities.

The Teleological Argument

3. God provides the best explanation for the complex order in the universe. During the last thirty years, scientists have discovered that the existence of intelligent life depends upon a complex and delicately balanced set of initial conditions simply given in the Big Bang itself. We now know that life-prohibiting universes are vastly more probable than life- permitting universes like ours. How much more probable? Well, before I give you an estimation, let me just give you some numbers to give you a feel for the odds. The number of seconds in the history of the universe is about 1018, that's ten followed by eighteen zeros. The number of subatomic particles in the entire universe is about1080. 

Now with those numbers in mind, consider the following. Donald Page, one of America's eminent cosmologists, has calculated the odds of our universe existing as on the order of one chance out of 1010(123), a number which is so inconceivable that to call it astronomical would be a wild understatement!

Robert Jastrow, the head of NASA's Goddard Institute for Space Studies, has called this the most powerful evidence for the existence of God "ever to come out of science." Once again, the view that Christian theists have always held, that there is an intelligent designer of the Cosmos, seems to me to be much more plausible than the atheistic interpretation of chance.

The Moral Argument 

4. God provides the best explanation for the existence of objective moral values in the world.  If God does not exist, then objective moral values do not exist. Many theists and atheists alike concur on this point. For example, the late J.L. Mackie of Oxford University, one of the most influential atheists of our time, admitted, "If...there are...objective values, they make the existence of a god more probable than it would have been without them. Thus we have a...defensible...argument from morality to the existence of a god. 

But in order to deny God's existence, Mackie therefore denied that objective values exist. He wrote, "It is easy to explain this moral sense as a natural product of biological and social evolution."  Professor Michael Ruse, a philosopher of science at the University of Guelph, agrees. He explains:

Morality is a biological adaptation no less than are hands and feet and teeth.... Considered as a rationally justifiable set of claims about an objective something, [ethics] is illusory. I appreciate that when somebody says, `Love thy neighbor as thyself,' they think they are referring above and beyond themselves.... Nevertheless, ... such reference is truly without foundation. Morality is just an aid to survival and reproduction, ... and any deeper meaning is illusory.... 

Friedrich Nietzsche, the great atheist of the last century who proclaimed the death of God, understood that the death of God meant the destruction of all meaning and value in life. I think that Friedrich Nietzsche was right. But we've got to be very careful here. The question here is not, "Must we believe in God in order to live moral lives?" I'm not claiming that we must. Nor is the question, "Can we recognize objective moral values without believing in God?" I think that we can. Rather, the question is, "If God does not exist, do objective moral values exist?" Like Mackie and Ruse, I just don't see any reason to think that in the absence of God, the morality evolved by homo sapiens is objective. After all, if there is no God, then what's so special about human beings? They're just accidental by-products of nature which have evolved relatively recently on an infinitesimal speck of dust called the planet Earth, lost somewhere in a hostile and mindless universe, and which are doomed to perish individually and collectively in a relatively short time. 

On the atheistic view, some action, say, rape, may not be socially advantageous and so in the course of human evolution has become taboo. But that does absolutely nothing to prove that rape is really wrong. On the atheistic view, if you can escape the social consequences, there's nothing really wrong with your raping someone. Thus, without God there is no absolute right and wrong which imposes itself on our conscience. 

But the fact is that objective moral values do exist, and we all know it. There's no more reason to deny the objective existence of moral values than to deny the objective reality of the physical world. Actions like rape, torture, and child abuse aren't just socially unacceptable behavior. They're moral abominations. Even Ruse himself admits, "The man who says that it is morally acceptable to rape little children is just as mistaken as the man who says two plus two equals five." Some things are really wrong. Similarly, love, equality, and self-sacrifice are really good.

But if objective values cannot exist without God, and objective values do exist, then it follows logically and inescapably that God exists.

The Experience of God

5. God can be immediately known and experienced.  This isn't really an argument for God's existence, rather it's the claim that you can know God exists wholly apart from arguments simply by immediately experiencing Him. This was the way that people in the Bible knew God, as Professor John Hick explains:

God was known to them as a dynamic will interacting with their own wills, a sheer,    given reality, as inescapably to be reckoned with as destructive storm and life-giving sunshine.... They did not think of God as an inferred entity, but as an experienced reality.... To them God was not...an idea adopted by the mind, but the experiential reality which gave significance to their lives.

Now if this is the case, arguments for God can actually distract our attention from God Himself. If you are sincerely seeking God, if this is not an intellectual game, then God will make His existence evident to you. The Bible promises, "Draw near to God, and He will draw near to you" (James 4:8). We mustn't so concentrate on the arguments that we fail to hear the inner voice of God to our own hearts. For those who listen, God becomes an immediate reality in their lives. 

Conclusion

So in conclusion, then, we've yet to see any arguments to show that God does not exist, and we have seen six reasons to think that God does exist. Together these constitute a powerful, cumulative case for the existence of God. If we are to believe atheism instead, then Dr. Washington is first going to have tear down all six of the reasons that I've presented in favor of God's existence and then in their place erect a case of his own in favor of atheism. Unless and until he does that, I hope that we can agree that theism is the more plausible world view.