Ok I'll address this, which I googled:
In more abstract philosophical language, the proof goes this way. Every being that exists either exists by itself, by its own essence or nature, or it does not exist by itself. If it exists by its own essence, then it exists necessarily and eternally, and explains itself. It cannot not exist, as a triangle cannot not have three sides. If, on the other hand, a being exists but not by its own essence, then it needs a cause, a reason outside itself for its existence. Because it does not explain itself, something else must explain it. Beings whose essence does not contain the reason for their existence, beings that need causes, are called contingent, or dependent, beings. A being whose essence is to exist is called a necessary being. The universe contains only contingent beings. God would be the only necessary being—if God existed. Does he? Does a necessary being exist? Here is the proof that it does. Dependent beings cannot cause themselves. They are dependent on their causes. If there is no independent being, then the whole chain of dependent beings is dependent on nothing and could not exist. But they do exist. Therefore there is an independent being.
Saint Thomas has four versions of this basic argument.
First, he argues that the chain of movers must have a first mover because nothing can move itself. (Moving here refers to any kind of change, not just change of place.) If the whole chain of moving things had no first mover, it could not now be moving, as it is. If there were an infinite regress of movers with no first mover, no motion could ever begin, and if it never began, it could not go on and exist now. But it does go on, it does exist now. Therefore it began, and therefore there is a first mover.
Second, he expands the proof from proving a cause of motion to proving a cause of existence, or efficient cause. He argues that if there were no first efficient cause, or cause of the universe's coming into being, then there could be no second causes because second causes (i.e., caused causes) are dependent on (i.e., caused by) a first cause (i.e., an uncaused cause). But there are second causes all around us. Therefore there must be a first cause.
Third, he argues that if there were no eternal, necessary, and immortal being, if everything had a possibility of not being, of ceasing to be, then eventually this possibility of ceasing to be would be realized for everything. In other words, if everything could die, then, given infinite time, everything would eventually die. But in that case nothing could start up again. We would have universal death, for a being that has ceased to exist cannot cause itself or anything else to begin to exist again. And if there is no God, then there must have been infinite time, the universe must have been here always, with no beginning, no first cause. But this universal death has not happened; things do exist! Therefore there must be a necessary being that cannot not be, cannot possibly cease to be. That is a description of God.
Fourth, there must also be a first cause of perfection or goodness or value. We rank things as more or less perfect or good or valuable. Unless this ranking is false and meaningless, unless souls don't really have any more perfection than slugs, there must be a real standard of perfection to make such a hierarchy possible, for a thing is ranked higher on the hierarchy of perfection only insofar as it is closer to the standard, the ideal, the most perfect. Unless there is a most-perfect being to be that real standard of perfection, all our value judgments are meaningless and impossible. Such a most-perfect being, or real ideal standard of perfection, is another description of God.
There is a single common logical structure to all four proofs. Instead of proving God directly, they prove him indirectly, by refuting atheism. Either there is a first cause or not. The proofs look at "not" and refute it, leaving the only other possibility, that God is.
The problem I have with these arguments is that they assume time is a "universal" constant. Time exists within the universe; we have no knowledge that it exists outside the universe (unfounded assumption). Without the universe we don't have the universe's time reference. You can't say God existed for an infinite amount of time, then he decided to create the universe, and did so. It doesn't make sense. How can God be governed by something that doesn't exist yet? The relationship between two objects existing outside the universe's "time" frame (ie. the universe as a whole and God) cannot have time relationships. This seems fundamental to me. Without time both either exist or don't exist. Observation says the universe exists.
The universe is a 4 dimensional object composed of "processes". These processes give rise to the 4 dimensions we perceive: 3 spatial and 1 time. These processes converge to form a point we call the big bang.
There is "before" the big bang as we know it. Time doesn't exist prior to this point (its even silly of me to be using these words, its best to say space-time converges to the big bang). Whatever philosophical argument that describes actions within this universe, if it desires to know the happenings of a location on the space-time continuum that does not exist (ie. What was there 3 seconds "before" the big bang?
C. S. Lewis put it, "I felt in my bones that this universe does not explain itself."
Smart guy I guess. No knowledge of space-time. He might as well be discussing the eating habits of the loch ness monster, rather than the happenings "before" the big bang.
