By objective moral laws, I mean standards that designate something as either moral or immoral, regardless of a person’s opinion about them. Someone might say, “Something is only immoral when the majority of people think it is immoral.” However, morality cannot be based entirely on majority opinion. We know from experience that the majority can be wrong about morality. Slavery is just one obvious example. It is always immoral to kidnap people and force them to work against their will. It is never morally permissible to treat human beings like property. On the other hand, if objective morals did not exist, then someone like William Wilberforce would not have been objectively moral in his fight to end the slave trade in England. He would simply have been expressing his subjective opinions and feelings. Martin Luther King Jr. would merely have been pleading for racial equality in the United States based on his personal preferences. In fact, if morality were merely determined by majority opinion, then these men would need to be labeled immoral. After all, they fought against the mainstream views of their time. We intuitively know that to be absurd. These men and many others have stood for objective morality, even against the majority opinion.
Given the existence of God, it is easy to explain the reality of objective moral laws; they are eternally grounded in His character and subsequent commands. However, if God did not exist, there would be no way to account for the existence of objective moral laws. While objective morality may be known to a man apart from his belief in God; it simply cannot exist in the absence of God. Consider the words of respected atheist Michael Ruse, philosopher of science at Florida State University. He expresses the logical conclusion of atheism concerning morality. According to Ruse,
"The position of the modern evolutionist… is that humans have an awareness of morality… because such an awareness is of biological worth. Morality is a biological adaptation no less than are hands and feet and teeth. … Considered as a rationally justifiable set of claims about an objective something, ethics is illusory. I appreciate that when somebody says, 'Love thy neighbor as thyself,' they think they are referring above and beyond themselves… Nevertheless… such reference is truly without foundation. Morality is just an aid to survival and reproduction… and any deeper meaning is illusory."
If morality is simply a biological adaptation--the result of evolution--then we cannot condemn any behavior as objectively evil or wrong. Consider what Charles Darwin himself wrote in The Descent of Man. He writes,
"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."
Obviously, we do not condemn animals for such behavior. They are not morally accountable. Richard Taylor explains: “A hawk that seizes a fish from the sea kills it, but it does not murder it; and another hawk that seizes the fish from the talons of the first takes it, but it does not steal it – for none of these things is forbidden.” To say that something is forbidden is to raise the question “by whom?” Therefore, if God did not exist, then no behavior would be forbidden--human or otherwise. If atheism were true, then morality might have been dramatically different, if we had only evolved in some other manner. However, if that were true, then morality would be entirely arbitrary.
The truth is that objective morality simply would not exist if we lived in a purely physical universe. As you can see, that is not merely my conclusion, but also the conclusion of logically consistent naturalists. However, such a conclusion goes against all of our experience and observation. We intuitively know that objective moral laws exist. Some things are always wrong, even if the majority disagrees. Since objective moral laws exist, a transcendent, objective moral lawgiver must also exist.
There are other moral experiences that would also be illusory if human beings were simply biological machines. The foremost of these would be freedom of the will. If a man’s thoughts were nothing more than random, biochemical reactions occurring in a lump of tissue called a brain, then he would not be free in any meaningful sense. Rather, he would be at the mercy of his biology. Morality would have no meaning in such a scenario. Atheists like Sam Harris unashamedly acknowledge this fact and claim that free will is illusory. Pondering the consequences of such a theory, Harris remarks, “While it’s conceivable that someone, somewhere, might be made worse off by dispensing with the illusion of free will, I think that on balance, it could only produce a more compassionate, equitable, and sane society.” One has to wonder what Harris means when he says “I think.” There is an implied sense of freedom in saying, “I think.” The implication, of course, is that one has pondered the evidence and freely drawn a conclusion. However, if there is no freedom of the will, then Harris is not thinking freely. There is no reason for him or his readers to trust his conclusions. His view requires that his conclusions were reached through an unguided, purposeless, biological process. However, his view also necessitates that the same must be true of any person who disagrees with his conclusions. The logical result would be that neither of them could be right in any meaningful sense.
Additionally, it is difficult to make sense of Harris’ comment that, “it could only produce.” Once again, there is an implied element of freedom in his statement. The implication is that free agents can consider Harris’ claims and respond appropriately. Yet, if free will were merely an illusion, then people would only be capable of doing what their biology dictated. There would be no sense in hoping that people would thoughtfully consider Harris’ conclusions and modify their behavior accordingly. Such a notion is entirely irrational on a naturalist view. Harris simply equivocates on the meaning of free will--assuming that just enough exists to make his theory work.
Moral accountability would also evaporate if freedom of the will did not exist. There would be no reason to condemn a man for doing something about which he had absolutely no choice. We see this played out in our legal system. If it can be demonstrated that a person had no choice except to commit a crime--due to a chemical imbalance, insanity, or coercion--they will not be punished in the same way as if they had been truly free. We intuitively know that we cannot blame someone for doing something they are biologically incapable of avoiding. The fact that we condemn people for immorality reflects a shared awareness that objective moral standards exists, and that we, as free moral agents, are responsible for our actions.
In addition to moral accountability, we would also have to do away with moral virtues if free will were illusory. On such a worldview, virtues like love, kindness, and bravery simply disappear. It would be of no objective moral value for a mother to tell her child, “I love you” if it were merely the result of a random chemical reaction. After all, her feelings might be changed with the reworking of her brain chemistry. Similarly, there would be no objective moral difference between a soldier who fights for freedom and a serial killer who mutilates people for pleasure. Both men would simply be following their biological programming. With the right combination of drugs we might be able to make a vicious murder out of the former and a courageous soldier out of the latter. There would be no objective moral value to one or the other. The mere thought should strike you as monstrous. To put it bluntly, we know better.
If objective moral laws exist, a transcendent, objective moral law giver must also exist. I have demonstrated that objective morality makes the most sense of the world as we know it. Society would crumble without moral accountability, freedom of the will, and moral virtues--all of which are inextricably linked to the existence of objective moral laws. Since objective moral laws exist, a transcendent, objective moral law giver also exists. God is the best explanation for the existence of objective moral laws.
 Michael Ruse, “Evolutionary Theory and Christian Ethics,” in The Darwinian Paradigm (London: Routledge, 1989), 262, 268-89.
 Charles Darwin, The Descent of Man and Selection in Relation to Sex 2nd Ed. (New York, NY: D. Appleton & Company, 1909), p. 100.
 Richard Taylor, Ethics, Faith, and Reason (Buffalo, NY: Prometheus, 1988), 73.
 Sam Harris, “Life Without Free Will,” http://www.samharris.org/blog/item/life-without-free-will (Accessed September 26, 2013).