The Moral Argument. This argument can find its roots in philosophers such as Thomas Aquinas, Immanuel Kant, and it is also employed by C.S. Lewis in Mere Christianity. The argument goes as follows:
If God does not exist, then objective moral values do not exist.
Objective moral values do exist.
Therefore God exists.
I like this argument because it affects so much of the everyday decisions we make in life. It cuts right to the heart of our choices, and in that way feels very practical and meaningful. The first premise is probably the most difficult to defend. However, even some atheists (like Friedrich Nietzsche) believe that apart from God morality is not objective. Rather, morality is just a social game, it is relative and ultimately illusory. Additionally, even if objective moral values did exist on the atheistic worldview, there is no moral accountability. Why should one choose to be kind to their neighbor and not cruel to their neighbor? Furthermore, due to the nature of morality it is evident that one ought to do certain things and ought not do other things, which seems to imply some kind of command to whom the duty is owed. So, I think the premise is warranted. What about the second premise that objective moral values do exist? I think that this premise is evidently true. Good and evil really do exist; they aren't just social conventions. How could we talk about moral progress if they didn't? To say that society has gotten better or improved is to hold it up to some moral standard. Additionally, how could we condemn acts as really evil, if evil was simply relative. As William Lane Craig points out, "The holocaust was objectively wrong even though the Nazis thought it was right, and it would still have been even if the Nazis had won the war and brainwashed everyone who disagreed with them." So it seems undoubtedly clear that objective moral values exist. Thus, God exists.
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