An argument for the existence of God goes something like this: People have absolute standards of morality. These standards had to have come from somewhere, and this must have been God.
Absolute standards of morality
Do people really have absolute standards of morality? At first glance, some might say yes. For example, the vast majority of people on earth will say things like murder, slavery and child rape are clearly wrong. However, with a closer look at human society and history, things are not quite so black and white.
Moral standards throughout history
Even something as basic as the wrongness of killing another human being is not so clear cut. People will argue as to if, or to what extent, the death penalty or killing in war is justified. The extremes of thinking range from those who do not want to hurt plants and insects to people who manage to justify very bloody deeds (to include killing for God) as moral (in their minds anyway).
In addition, what is considered murder is also culturally relative. For example, in many cultures, it was ok to leave newborns and young children to die (as well as the old in some situations). In others, human sacrifice, sometimes for God, was also justified. This list can go on with other examples to include those societies in which killing for revenge (or honor) is not only justified but the only culturally acceptable choice.
Of course, examples of how moral standards differ go far beyond when killing is justified. Slavery was considered part of the natural order of things and was thus considered morally justified by people throughout history. This is reflected everywhere from religious texts (see slavery & religion) to the writings of great thinkers like Aristotle.
It is also interesting to note that moral standards do not necessarily move in one direction as they gradually have moved away from condoning the institution of slavery. For example, attitudes towards sex have frequently moved between the more restrictive and relaxed within societies depending on the times (see god and sex).
The evolution of morality
If morality is not really absolute and relative to the time and place, where could it come from? Why do most people in the world today generally agree on at least some standards of morality? The answer probably lies in morality being something that is necessary for human survival which has evolved with society. Morality makes evolutionary sense since no social creature could survive without it, giving it natural survival advantage. For example, if nobody had any natural instincts to want to protect their young or human life, society could never have developed.
This is also true for social animals. While morality was once thought of something that was distinctly human, scientists now believe that forms of morality, from empathy to a sense of fairness, exist in a wide range of animals from mice to primates. Animals can tell right from wrong covers this topic in more detail.
Morality grows with people
The changes in morality can also be explained when it is looked upon not as an absolute but as an agreed-upon idea that reflects the values of people in a society. As science has progressed, human beings have been able to live longer and healthier with less physical labor. These and other factors have gradually led to more rule of law and greater emphasis on the individual and human rights. Along with these trends, people have grown to abhor institutions like slavery and put a higher value on human life.
If morality was from the divine and absolute, it would be reasonable to assume that people’s idea of it would have been very consistent throughout human history. In fact, humanity probably would be much better off if its standards of morality (at least in regard to human rights) had always been closer to what they generally are today. Unfortunately, morality as most people now know it shows every sign of being something that evolved with society and was not given to people.