The argument from design can be likened to a watch. A watch is obviously made by a watchmaker. The world, which is much more complex than a watch, must also have been designed by a great Designer or Divine Watchmaker (God).
In sum, the teleological argument asserts that the universe evidences too much complexity to be the product of random chance. We know that the celestial bodies move with perfect accuracy in their orbits. Our bodies, too, are incredibly complex. According to the teleological argument, there’s just no way all this complexity could “just happen.” God must have created it all."
The ontological argument can be stated in this way: “God is the greatest being imaginable. One of the aspects of perfection or greatness is existence. Thus, God exists.” Or put another way—“The fact that God can be conceived means that he must exist.”
This argument for God’s existence was developed by the twelfth century theologian and philosopher, Anselm. It is based on Anselm’s declaration that God is “that which nothing greater can be conceived.”"
This is the weakest argument of the four, by far, because it just begs the question: If something can be conceived, it must not necessarily exist. If you imagine perfection, and one of the aspects of perfection is existence, the leap between imagining perfection and stating that perfection exists is very unreasonable.
4: Moral Law Argument
"Another argument for the existence of God is the moral law argument. It goes like this: Without God morality would be impossible. There must be a Lawgiver (God) who originates and stands by moral law. A universal moral law cannot exist accidentally. There must be a basis behind it—God.
According to this view, every person is born with an inherent understanding of right and wrong. Everyone, for instance, understands that killing an innocent person is wrong. Everyone understands that helping a drowning person is right. Where did this internal understanding of right and wrong come from? According to adherents of the moral law argument, this understanding comes from God. He put it into the hearts of every person."
Vlach goes on to mention that there are two reactions to this - relatavism, or that objective good/evil does not exist, and that if God is all good, then why would there be evil in the world?
Of course, then, there is Rand's argument, that there does exist an objective good/evil inherent in human nature, but it is not from any external means. She claims that good is that which enables humans to flourish, and it is not relative from culture to culture or person to person. As Drew mentioned to me once, it seems that there must have been a "fall" at some point, for if everyone, acting in their own rational self interest was creating the best possible society, why would anyone act against this?
Still, to me, this argument seems to carry the most water, but the argument "Objective good/evil therefore God" hasn't won me over yet.
Vlach ends, most helpfully, with:
"It should be noted that most Christian theologians and philosophers believe that God never intended for his existence to be something that could be proven with 100% certainty. They point out that faith is an important component in understanding God and his existence."