What is the basis of our values?

The focus of my study (other than studying TCP/IP in college) has been on morality. Is it objective? Do we need God for morality? Has morality come from evolution? Do objective moral values and duties prove the existence of God? This could be summed up in a question, "What is the basis of our values?" I found the question in William Lane Craig's book, "On Guard" and I thought that was a good question for this post, therefore, we'll look at Bill Craig's moral argument for God's existence. 
What is the basis of our values? Are they based on social convention? Personal preference? Evolution? God? I would argue that they are based on God. I believe there is good evidence for that, as I've covered the moral arguments for God from Kant, Sorley, Nietzsche; they all come to the conclusion that God is needed for the objectivity of morality. William Lane Craig covers the argument well, I obviously cannot cover it in this single post, but I'll summarize his argument and leave links for further reading. 
Bill Craig's argument is as follows:
1. If God does not exist, objective moral values and duties do not exist. 
2. Objective moral values and duties do exist.
3. Therefore, God exists. 
A simple argument with a powerful conclusion. As Bill says in his book, "This simple little argument is easy to memorize and is logically ironclad."1 Generally, people believe the first two premises. Bill says that premise 1 seems correct to people because we live in a pluralistic age in which they're scared to death of imposing their beliefs on someone else. However, premise 2 seems correct to those same people because they believe it's objectively wrong to impose your values on someone else! Let's examine the premises more closely. 
Premise 1: If God does not exist, objective moral values and duties do not exist.
Moral value refers to the worth of a person or action, whether it is good or bad. Moral duty refers to our obligation to act in a certain way, whether that action is right or wrong.2 Now, lets define objective. Objective means independent of human opinion. Bill gives the example, "...the laws of nature hold whether we acknowledge them or not, so they are objective."3 Subjective means dependent on human opinion, e.g., matters of which baseball team is better, or taste, whether pizza or good or not; subjective is person-relative. 
Now, on to defending premise one. I've learned in studying the moral arguments for God, traditionally moral values have been based on God because He is the highest Good. If He doesn't exist, what is the basis of moral values? Why think we have moral worth? Naturalism (the most popular form of atheism) holds that the only things that exist are the things that can be tested by scientific theories. Science is morally neutral, so you can't find morality there. What follows then? That moral values are illusory, they don't exist. 
On a naturalistic view, there cannot be objective moral values. Man has developed a "herd morality" in order to survive, just like animals, so there is objectivity to morals on this view. Consider what Darwin wrote in The Descent of Man,
"If...men were reared under precisely the same conditions as hive-bees, there can hardly be a doubt that our unmarried females would, like the worker-bees, think it a sacred duty to kill their brothers, and mothers would strive to kill their fertile daughters; and no one would think of interfering." 4 
So, for the naturalist to think morality is objective, then he is committing speciesism, which is an unjustified bias to one's own species. 
I'll use Bill's own conclusion here:
"So if there is no God, any basis for regarding the herd morality evolved by Homo sapiens as objectively true seems to have been removed. Take God out of the picture, and all you're left with is an apelike creature on a speck of solar dust beset with delusions of moral grandeur." 5 
I'll cover more of this premise and the rest in later posts. So, what do you think? Do objective moral values and duties exist? Does Bill's argument convince you? 


Sources:
1. William Lane Craig, On Guard: Defending Your Faith with Reason and Precision (Colorado Springs, CO: David C. Cook, 2010), pg. 129
2. ibid, pg. 131
3. ibid, pg. 131
4. Charles Darwin, The Descent of Man and Selection in Relation to Sex, 2nd edition (New York: D. Appleton & Company, 1909), pg. 100
5. William Lane Craig, On Guard: Defending Your Faith with Reason and Precision (Colorado Springs, CO: David C. Cook, 2010), pg. 144


Links: 
Moral facts or moral beliefs?
God and Morality Debate: William Lane Craig vs. Torbjörn Tännsjö MP3 Audio 
Dinesh D'Souza vs. Peter Singer Debate: Can There Be Morality Without God? MP3 Audio 
William Lane Craig's book On Guard 
Paul Copan, Why Science Can't Explain Morality