This is an excerpt from an essay by William Lane Craig entitled Why I Believe God Exists which can be found here:
http://www.shakinandshinin.org/WhyIBelieveGodExists.html
I'm interested in reading what others may think of this. All comments are welcome. I hope its not too long. Thanks!
I. God Makes Sense of the Origin of the Universe
Have you ever asked yourself where the universe came from? Why everything exists instead of nothing? Typically, atheists have said that the universe is just eternal, and thats all. But surely this is unreasonable. If the universe never had a beginning, that means the number of past events in the history of the universe is infinite. But mathematicians recognize that the idea of an infinite number of things leads to self-contradictions. . . . This shows that infinity is just an idea in ones mind, not something that 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. Therefore, since past events are not just ideas but are real, the number of past events must be finite. Therefore, the series of past events cant go back forever; rather, the universe at some point must have begun to exist.
This conclusion has been confirmed by remarkable discoveries in astronomy and astrophysics. The astrophysical evidence indicates that the universe began to exist in a great explosion called the big bang around fifteen billion years ago. . . . Thus, what the big bang model requires is that the universe began to exist and was created out of nothing.
We can summarize the argument thus far as follows:
1. Whatever begins to exist has a cause.
2. The universe began to exist.
3. Therefore, the universe has a cause.
Given the truth of the first two premises, the third necessarily follows.
From the very nature of the case, as the cause of space and time, this supernatural cause must be an uncaused, changeless, timeless, and immaterial being that created the universe. The being must be uncaused because weve seen that there cannot be an infinite regress of causes. It must be timeless and therefore changeless 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 such as the universe? . . . 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.
What objections might be raised against this argument? Premise 1: The fact that whatever begins to exist has a cause seems obviously trueat least more so than its denial. Yet a number of atheists, in order to avoid the arguments conclusion, deny the first premise. Some say that subatomic physics furnishes an exception to premise 1, since on the subatomic level events are said to be uncaused. . . . [However,] even according to the traditional, indeterministic interpretation, particles do not come into being out of nothing. They arise as spontaneous fluctuations of the energy contained in the subatomic vacuum; they do not come from nothing.
Other atheists have said that premise 1 is true for things in the universe, but it is not true of the universe itself. But this objection misconstrues the nature of the premise. Premise 1 does not state merely a physical law such as the law of gravity or the laws of thermodynamics, which are valid for things within the universe. Premise 1 is not a physical principle. Rather, premise 1 is a metaphysical principle, a principle about the very nature of reality: Being cannot come from nonbeing; something cannot come into existence uncaused from nothing. [T]he potentiality of the universe lay in the power of God to create it.
So what about premise 2: The universe began to exist? The typical objection raised against the philosophical argument for the universes beginning is that modern mathematical set theory proves that an actual infinite number of things can exist. For example, there is an infinite number of members in the set {0, 1, 2, 3, . . . } . Therefore, theres no problem with an infinite number of past events.
But this objection does not work. First, not all mathematicians agree that actual infinities exist even in the mathematical realm. They regard series such as 0, 1, 2, 3, . . . as merely potentially infinite; that is to say, such series approach infinity as a limit, but they never actually get there. Second, existence in the mathematical realm does not imply existence in the real world. To say that infinite sets exist is merely to postulate a realm of discourse, governed by certain axioms and rules that are simply presupposed, in which one can talk about such collections. . . . Third, the real existence of an infinite number of things would violate the rules of infinite set theory.
As we saw, trying to subtract infinite quantities leads to self-contradictions; therefore, infinite set theory just prohibits such operations to preserve consistency. In the real world, however, theres nothing to keep us from breaking this arbitrary rule. If I had an infinite number of marbles, I could subtract or divide them as I please.
Sometimes its said that we can find counter examples to the claim that an infinite number of things cannot exist, so this claim must be false. For instance, isnt every finite distance capable of being divided into 1/2, 1/4, 1/8, . . . on to infinity? Doesnt that prove that in any finite distance there is an infinite number of parts? The fallacy of this objection is that it once again confuses a potential infinite with an actual infinite. You can continue to divide any distance for as long as you want, but such a series is merely potentially infinite; infinity serves as a limit you endlessly approach but never reach.
As for the scientific confirmation of premise 2, it has been the overwhelming verdict of the scientific community that no theory is more probable than the big bang theory. The devil is in the details, and once you get down to specifics, you find that there is no mathematically consistent model that has been so successful in its predictions or as corroborated by the evidence as the traditional big bang theory. . . . In sum, according to Hawking, Almost everyone now believes that the universe, and time itself, had a beginning at the Big Bang. 
In light of the evidence, premises 1 and 2 seem more plausible than their denials. Hence, it is plausible that a transcendent Creator of the universe exists. People sometimes resist this conclusion because they claim that it is a pseudo-explanation of the origin of the universe. Just because we cant explain it doesnt mean God did it, they protest. But such a response misconstrues the argument. In the first place, this argument is a deductive argument. Therefore, if the premises are true and the logic is valid, the conclusion follows, period. [Secondly, to say that God created the universe is a perfectly valid explanation, although a personal, not scientific, one.] It explains some effect in terms of an agent and his intentions. We employ such explanations all the time.
For example, if you were to come into the kitchen and find the kettle boiling and ask me, Why is the kettle boiling? I might give you an explanation in terms of the kinetic energy communicated to the water by the flame by means of the heat-conducting metal used in the manufacture of the kettle, which causes the molecules of the water in the kettle to vibrate faster and faster until they are thrown off in the form of steam. Or I might say, I put it on to make a cup of tea! Both are equally legitimate explanations, and in many contexts, only a personal explanation will do. In the case of cosmic origins, as Oxford philosopher Richard Swinburne points out, there cannot be a scientific explanation of a first state of the universe, since there is nothing before it. Therefore, if a personal explanation does not exist, then there is simply no explanation at allwhich is metaphysically absurd, since on that account the universe just popped into being uncaused out of nothing.
Other atheists have charged that the arguments conclusion is incoherent, since a cause must come before its effect, and there is no moment before the big bang. This objection, however, is easy to answer. Many causes and effects are simultaneous. Thus, the moment of Gods causing the big bang is the moment of the occurrence of the big bang. We can then say that God existed alone without the universe before the big bang, not in physical time but in an undifferentiated metaphysical time, or that he is strictly timeless and entered into time at the moment of creation. No incoherence has been shown in either of these alternatives.
But people will say, But if the universe must have a cause, then what is Gods cause? This question reveals an inattentiveness to the formulation of the argument. The first premise does not state, whatever exists has a cause, but rather, whatever begins to exist has a cause. The difference is important. The insight that lies at the root of premise 1 is that being cannot come from nonbeing, something cannot come from nothing. God, since he never began to exist, would not require a cause, for he never came into being. This is not a special pleading for God, since this is exactly what the atheist has always claimed about the universe: that it is eternal and uncaused. The problem is that the atheists claim is now rendered untenable in light of the beginning of the universe.
Finally, someone might wonder, But isnt God supposed to be infinite? Your argument shows that the infinite cannot exist. So how can God exist? In fact, the argument was that an infinite number of things cannot exist. God is not a collection of an infinite number of things. As a nonphysical being, he doesnt even have parts. When theologians speak of Gods infinity, they are thus using the term in a qualitative not a quantitative sense. They mean that God is absolutely holy, uncreated, self-existent, all-powerful, all-present, and so forth. Its not a mathematical concept. Thus, theres no contradiction.
In sum, we have a powerful reason based on the origin of the universe to believe that an uncaused, changeless, timeless, immaterial, personal Creator of the universe exists.
http://www.shakinandshinin.org/WhyIBelieveGodExists.html
I'm interested in reading what others may think of this. All comments are welcome. I hope its not too long. Thanks!
I. God Makes Sense of the Origin of the Universe
Have you ever asked yourself where the universe came from? Why everything exists instead of nothing? Typically, atheists have said that the universe is just eternal, and thats all. But surely this is unreasonable. If the universe never had a beginning, that means the number of past events in the history of the universe is infinite. But mathematicians recognize that the idea of an infinite number of things leads to self-contradictions. . . . This shows that infinity is just an idea in ones mind, not something that 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. Therefore, since past events are not just ideas but are real, the number of past events must be finite. Therefore, the series of past events cant go back forever; rather, the universe at some point must have begun to exist.
This conclusion has been confirmed by remarkable discoveries in astronomy and astrophysics. The astrophysical evidence indicates that the universe began to exist in a great explosion called the big bang around fifteen billion years ago. . . . Thus, what the big bang model requires is that the universe began to exist and was created out of nothing.
We can summarize the argument thus far as follows:
1. Whatever begins to exist has a cause.
2. The universe began to exist.
3. Therefore, the universe has a cause.
Given the truth of the first two premises, the third necessarily follows.
From the very nature of the case, as the cause of space and time, this supernatural cause must be an uncaused, changeless, timeless, and immaterial being that created the universe. The being must be uncaused because weve seen that there cannot be an infinite regress of causes. It must be timeless and therefore changeless 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 such as the universe? . . . 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.
What objections might be raised against this argument? Premise 1: The fact that whatever begins to exist has a cause seems obviously trueat least more so than its denial. Yet a number of atheists, in order to avoid the arguments conclusion, deny the first premise. Some say that subatomic physics furnishes an exception to premise 1, since on the subatomic level events are said to be uncaused. . . . [However,] even according to the traditional, indeterministic interpretation, particles do not come into being out of nothing. They arise as spontaneous fluctuations of the energy contained in the subatomic vacuum; they do not come from nothing.
Other atheists have said that premise 1 is true for things in the universe, but it is not true of the universe itself. But this objection misconstrues the nature of the premise. Premise 1 does not state merely a physical law such as the law of gravity or the laws of thermodynamics, which are valid for things within the universe. Premise 1 is not a physical principle. Rather, premise 1 is a metaphysical principle, a principle about the very nature of reality: Being cannot come from nonbeing; something cannot come into existence uncaused from nothing. [T]he potentiality of the universe lay in the power of God to create it.
So what about premise 2: The universe began to exist? The typical objection raised against the philosophical argument for the universes beginning is that modern mathematical set theory proves that an actual infinite number of things can exist. For example, there is an infinite number of members in the set {0, 1, 2, 3, . . . } . Therefore, theres no problem with an infinite number of past events.
But this objection does not work. First, not all mathematicians agree that actual infinities exist even in the mathematical realm. They regard series such as 0, 1, 2, 3, . . . as merely potentially infinite; that is to say, such series approach infinity as a limit, but they never actually get there. Second, existence in the mathematical realm does not imply existence in the real world. To say that infinite sets exist is merely to postulate a realm of discourse, governed by certain axioms and rules that are simply presupposed, in which one can talk about such collections. . . . Third, the real existence of an infinite number of things would violate the rules of infinite set theory.
As we saw, trying to subtract infinite quantities leads to self-contradictions; therefore, infinite set theory just prohibits such operations to preserve consistency. In the real world, however, theres nothing to keep us from breaking this arbitrary rule. If I had an infinite number of marbles, I could subtract or divide them as I please.
Sometimes its said that we can find counter examples to the claim that an infinite number of things cannot exist, so this claim must be false. For instance, isnt every finite distance capable of being divided into 1/2, 1/4, 1/8, . . . on to infinity? Doesnt that prove that in any finite distance there is an infinite number of parts? The fallacy of this objection is that it once again confuses a potential infinite with an actual infinite. You can continue to divide any distance for as long as you want, but such a series is merely potentially infinite; infinity serves as a limit you endlessly approach but never reach.
As for the scientific confirmation of premise 2, it has been the overwhelming verdict of the scientific community that no theory is more probable than the big bang theory. The devil is in the details, and once you get down to specifics, you find that there is no mathematically consistent model that has been so successful in its predictions or as corroborated by the evidence as the traditional big bang theory. . . . In sum, according to Hawking, Almost everyone now believes that the universe, and time itself, had a beginning at the Big Bang. 
In light of the evidence, premises 1 and 2 seem more plausible than their denials. Hence, it is plausible that a transcendent Creator of the universe exists. People sometimes resist this conclusion because they claim that it is a pseudo-explanation of the origin of the universe. Just because we cant explain it doesnt mean God did it, they protest. But such a response misconstrues the argument. In the first place, this argument is a deductive argument. Therefore, if the premises are true and the logic is valid, the conclusion follows, period. [Secondly, to say that God created the universe is a perfectly valid explanation, although a personal, not scientific, one.] It explains some effect in terms of an agent and his intentions. We employ such explanations all the time.
For example, if you were to come into the kitchen and find the kettle boiling and ask me, Why is the kettle boiling? I might give you an explanation in terms of the kinetic energy communicated to the water by the flame by means of the heat-conducting metal used in the manufacture of the kettle, which causes the molecules of the water in the kettle to vibrate faster and faster until they are thrown off in the form of steam. Or I might say, I put it on to make a cup of tea! Both are equally legitimate explanations, and in many contexts, only a personal explanation will do. In the case of cosmic origins, as Oxford philosopher Richard Swinburne points out, there cannot be a scientific explanation of a first state of the universe, since there is nothing before it. Therefore, if a personal explanation does not exist, then there is simply no explanation at allwhich is metaphysically absurd, since on that account the universe just popped into being uncaused out of nothing.
Other atheists have charged that the arguments conclusion is incoherent, since a cause must come before its effect, and there is no moment before the big bang. This objection, however, is easy to answer. Many causes and effects are simultaneous. Thus, the moment of Gods causing the big bang is the moment of the occurrence of the big bang. We can then say that God existed alone without the universe before the big bang, not in physical time but in an undifferentiated metaphysical time, or that he is strictly timeless and entered into time at the moment of creation. No incoherence has been shown in either of these alternatives.
But people will say, But if the universe must have a cause, then what is Gods cause? This question reveals an inattentiveness to the formulation of the argument. The first premise does not state, whatever exists has a cause, but rather, whatever begins to exist has a cause. The difference is important. The insight that lies at the root of premise 1 is that being cannot come from nonbeing, something cannot come from nothing. God, since he never began to exist, would not require a cause, for he never came into being. This is not a special pleading for God, since this is exactly what the atheist has always claimed about the universe: that it is eternal and uncaused. The problem is that the atheists claim is now rendered untenable in light of the beginning of the universe.
Finally, someone might wonder, But isnt God supposed to be infinite? Your argument shows that the infinite cannot exist. So how can God exist? In fact, the argument was that an infinite number of things cannot exist. God is not a collection of an infinite number of things. As a nonphysical being, he doesnt even have parts. When theologians speak of Gods infinity, they are thus using the term in a qualitative not a quantitative sense. They mean that God is absolutely holy, uncreated, self-existent, all-powerful, all-present, and so forth. Its not a mathematical concept. Thus, theres no contradiction.
In sum, we have a powerful reason based on the origin of the universe to believe that an uncaused, changeless, timeless, immaterial, personal Creator of the universe exists.
