If you listen to them for very long, you will hear them talk about the need for early man to band together in groups for protection. Because these groups were better able to flourish than individuals who had not banded together, the traits that led these "group minded" people had the opportunity to be passed to future generations while the traits of those who were "individual minded" died out. Over the centuries, we inherited the traits of the "group minded" people and this is the reason we all feel moral obligations toward one another today.
While I agree that there is some merit to the idea that early man may have learned the advantages of living in groups for protection and mutual benefit, I don't think this idea fully explains our sense of moral duties and obligations. In a recent conversatio with someone who subscribes to this view, I listed a number of limitations that I see with this idea. Below is the list I generated from our discussion:
- In the evolutionary model, the most horrible things could be considered moral if they enhanced survivability. As an extreme example, if it enhanced survivability to ingest certain nutrients that could only be obtained from live infants, and if these nutrients were only produced when the child was undergoing the most intense suffering, then cannibalizing live children to feed on these nutrients would be considered moral.
- The evolutionary model is fully deterministic, but in order for moral duties to make any sense there must be the ability for someone to choose to behave in a moral way (also known as 'libertarian free will'). On the deterministic model, there is no free will and thus one cannot choose to behave in either a moral or an immoral way. Instead, our behaviors are fully determined by external causes over which we have no control. To put it another way, if I feel that I ought to treat a child with kindness (if I have a moral duty to do this), then that implies that I can make the choice to do this. On the evolutionary model, I don't have the ability to choose anything, so how can I be morally obligated to anything?
- While the idea of groups banding together for survival has merit in that it provides an opportunity for early man to learn that some behaviors are "better than" others, it ultimately fails as an explanation for morality since it cannot account for people's behavior when in power. On the evolutionary model, people should be "imprinted" with the desire to share with, care for, and protect the group. The argument is that if someone chooses not to participate in this, then they will be cast out of the group and thus their survival is questionable. But what about people in positions of power? They can (and do) choose to abandon this notion of "group mindedness" and they suffer no consequences as a result. Examples of this include Pol Pot, Mao Tse Tung, and Joseph Stalin. Each of these men brutalized people, but the predicted consequences of the evolutionary model did not occur.
- On evolution, heinous acts such as those of Adolf Hitler are perfectly legitimate if they serve to enhance the survivability of the group. In Hitler's case, he was trying to establish/maintain a pure Aryan bloodline. In this sense, his efforts to eliminate the "inferior" bloodline of groups such as the Jews, gypsies, homosexuals, and minorities were fully consistent with Darwinian principles.
Evolution may well serve as a partial explanation for how many came to discover certain moral traits. But evolution alone has no ability to explain whether objective moral duties exist in the first place. Further, the evolutionary explanation also opens the door for many of the awful things we've seen as recently as the mid 20th century. It's grounding in the Materialistic worldview also brings into the question whether there is any such thing as free will in the first place. And if there isn't, then moral obligations can't be said to exist in any case.
The problem is that we all know we have moral obligations. There are things we should do and others that we should not do. Because we know that these moral obligations exist, we must conclude that we have the ability (the libertarian free will) to choose whether to do them or not. And when we reach that conclusion, we must simultaneously conclude that morality is more than simply an artifact of man's evolutionary heritage.