During our conversation, Higgs was very interested in the morality argument. The morality argument, in a nutshell, is that a common morality, or a well grounded ethic, is not possible without a belief in God. However, before I go into the argument itself, there are a few of things that need to be explained.
First of all, the morality argument is not an argument for God's existence. It is relatively simple for an atheist to simply say, "well, I guess there's not morality" even when you demonstrate the logic of the argument is solid. All you can demonstrate is that it behooves a society to believe in God.
Second, it is not an apologetic argument but a polemical one. Apologetics is the art or practice of defending a position. Polemics is the art or practice of criticizing a position. It is important to understand that this argument isn't really defending Christianity; it is criticizing atheism. Atheists seem to have trouble with this, since they view themselves as having a kind of non-position, like people who don't think they have an accent. But, of course, it is a position. Even people without a fully formed opinion have a position. After all, a moving train is still somewhere. Each of us, regardless of how formed our positions are, have made decisions, ruled out possibilities, and have established what kinds of criteria we take seriously. The fact that atheists have trouble admitting this is one of the many reasons that they end up coming off as arrogant, and also one of the many reasons why the fail to understand simple arguments like this one.
The third thing is that a major reason why this argument comes up is because atheists attempt to criticize God on moral grounds. However, this is non-sensical, since they have no moral basis from which to critize (or so the argument goes).
Finally, we need to establish before diving in is that there is a difference between morality and ethics. Ethics is the systematization of moral behaviors. It is the understanding of the difference between right and wrong. Morality on the other hand is the personal sense of right and wrong: the motivations inside of us which guides us into making such decisions. Ethics is of the head, morality is of the heart. Ethics is morality in theory, morality is ethics in practice. Atheism has trouble with both of these concepts, but I will treat them in turn.
The basic morality argument is the moral behavior cannot be expected without a judge. For true morality to exist within a culture or society, there must be an expectation of justice. That fundamental need for order and reason in the cosmos is a fundamental need for humans psychologically. That is why children who are not disciplined often yearn it, while acting immorally.
Just look at the world around us! Often good people suffer, and evil people excel. It is unjust, and we know it. But what motivation is there for someone to obey the rules if there is no guarantee that those rules will bring safety or stability. If there is no law-giver, then there is no law. We become a law unto ourselves, which generally yields selfishness.
Many times Atheists criticize the justice of God by complaining about Him being a judge over us. But God being a judge is the foundation of justice. If God does not ultimately punish those who are wicked and ultimately reward the righteous, than there is no justice, and morality is a sham. So even though this doesn't prove God exists, it does show that society cannot stand without Him.
There are two basic ethical standards that have been proposed within the context of a secular society: hedonism and utilitarianism.
Utilitarianism is the belief that goodness is ultimately defined by what is best for the society. "It is the greatest happiness of the greatest number that is the measure of right and wrong." On the surface it seems like a very positive way to deal with the ethical problem, but it has some major problems.
First, like all forms of consequentialism, it lacks practicability. Because you are defining what is right or wrong based off of consequence, you can never truly know whether you are acting morally until long after the deed is done. While such a system may make sense for an omniscient being, for us humans there is no way of fully knowing the ultimate results of our actions. Therefore, how can we ever truly know if what we are doing is ethical?
Second, it can be used to justify almost anything. Even though we don't fully know the consequences of our actions, we can speculate. However, we are much poorer at speculating than we like to admit. If we have a reason for wanting to force a certain outcome, we can often justify any action to achieve. Utilitarianism empowers such justification. Good examples of the dangers of this ethic can be found in the character of Ozymandias from Watchmen, or from the characters from The Company in Heroes. In both cases you have people willing to sacrifice thousands or millions of lives for the sake of all of humanity. Indeed, Heroes is an even better example, because the future they were hoping to build with their sacrifice doesn't come to pass even in the cases where they succeed. It is a scary scary thing for mortals to play god.
Third, it has no power in generating morality. While it almost makes sense for politicians and world leaders, it doesn't seem to apply to the average Joe. How would a belief in the ultimate benefit for society really affect my choices in the day to day decisions of my life? And if the ethic of a society has no moral power for the denizens of that society, then it has no real moral power for the society as a whole either.
Hedonism is the belief that morality should be defined by the pursuit of pleasure, and the eschewal of pain. This is not only within one's self, but also in regards to those around one. Unlike Utilitarianism, which is focused outwardly, Hedonism is focused inwardly, and doesn't have the same problem of moral impotence. But it certainly has its own problems.
First of all, since it is usually conceived as a form of consequentialism, it can therefore lack the same practicability that I mentioned above. It is impossible for anyone to truly know how much pleasure or pain would actually yield from a particular event or action. For instance, will a particular relationship bring you happiness or pain? How do you know? How do you compare the joy of a baby in your arms to a teenager who has become a criminal and shamed your family?
Second it places certain things into moral categories which really shouldn't be. Playing games, or having children should be seen as moral choices within Hedonism, since they yield pleasure/pain. However, they are amoral activities, in of themselves.
Third, it can be used to justify many things that I at least would consider immoral, such as gluttony, the euthanasia of children, and other actions which may make life easier for a person, but degrades their character. It often descends into a kind of selfishness, either a pure egotism, or too much of a focus on one's own social circle to the neglect of charity.
The Christian Ethic
So what is the Christian ethic? I am only going to go over this briefly since this post is already much longer than I had though it would be. The Christian ethic is based on two ideas (which are interconnected IMO): that humans are made in the image of God, and that Christians are called to represent God.
In regards to the first point, because we are made in God's image, every human has an innate dignity. This includes all races, classes, genders, intelligence quotient, or lifestyle. While external cultural and political pressures have suppressed this in history, the essential Christian understanding of humanity means that there is a respect that we have for all people. Christ died for all of humanity, even the sinful. We are called to love all, even our enemies. This universal love defines Christianity and is the ultimate guide to how we interact with others.
In regards to the second point, because we are called to represent God, we seek to imitate Him. The truly moral Christian is one who behaves like Christ. We don't fall into the flaws of relying on consequences, but instead focus on the transformation of our internal character based on a model. This makes Christian ethics far more practicable then its atheist counterparts, and allows us to be able to be forgiven, and move past former mistakes.
While all this doesn't prove that Christianity is true, it does show that when Christianity is actually followed within a society, it is better for that society.