The evolution of morality
Authors: Callender John S. 
Published: February 2013

The main conclusion of this chapter is that morality is not a pristine exercise in rationalist philosophy or something that has been conferred upon us by divine blessing. Instead it is part of our nature and exists because it served our evolutionary purposes of survival and reproduction. Animals form social groups for the purposes of mutual protection and food gathering. Even a large herbivore like an elephant will be killed by predators if it is isolated from the herd.

As with many other animals, the solitary human is too weak to resist predation or to hunt for food. Sexual reproduction and the protection and rearing of offspring to maturity entail cooperative effort over an extended period. Survival depended on the formation of social groups that were stable, cohesive, and effective. There was a need to develop mechanisms to distribute the work and the resources of the group. Furthermore, there was a need for mechanisms to resolve conflict. A system of rules was required along with sanctions to ensure compliance with these rules. Small groups or tribes have always been vulnerable to attack by larger groupings. It was therefore necessary to maintain the allegiance of group members to avoid defection. One means by which this was achieved was ensuring that individuals were treated in a way that they perceived as being fair. Moral rules evolved over millions of years to promote and sustain successful group living.

Moral behavior in humans has foundations that exist in other animals. As is the case with some other social animals, we have spontaneous emotional responses to the suffering of others. We have the capacity to empathize with this suffering by assessing the situation and understanding the reasons for the emotions of the other person. We have the ability to adopt the other person's perspective and to take action on this understanding.

We understand many of our basic characteristics as consequences of our evolutionary history. These include our anatomy and physiology, our instinctual drives, and many of our behaviors. To exclude morality from this explanatory scheme is to separate it from the rest of life and to make its relationship to other parts of our lives unintelligible (Midgley, 1994).

It is important not to take too narrow a view of what evolution means for moral obligation. On a narrow view, one could argue that, if morality has evolved as an aid to survival, it is simply inappropriate to have any sense of obligation to people outside one's social group and completely irrational to accord moral worth to nonhuman species. Nature should be seen as nothing more than a resource to be ruthlessly exploited for our own benefit. If we were to learn that the last Bengal tiger or the last snow leopard had been shot, we should feel nothing but triumph and relief.

Yet the reality is quite different. Most people respond to the news of man-made extinctions of species with disquiet and guilt. Some of this may be no more than the projection of positive human traits onto animals in the way that we more commonly project our negative side. We can admire large predators for their dignity, grace, speed, and strength because these are things that we admire in ourselves. We would certainly feel more regret over the extinction of tigers than the extinction of rattlesnakes.

However, there may also be a wider sense that we are part of the natural world and that our future well-being is bound to the well-being of nature. Robert Burns (1993, 131) wrote a poem To a Mouse, after he had destroyed the nest of a humble field mouse with his plough:

I'm truly sorry Man's dominion

Has broken Nature's social union

An’ justifies that ill opinion,

Which makes thee startle,

At me, thy poor, earth-born companion,

An’ fellow-mortal!

There is perhaps wisdom in these moral sentiments. The world of nature is complex and vulnerable. We are now seeing around us the consequences of our selfish overexploitation of the natural world such as depletion of fish stocks, erosion of arable land, environmental pollution, bovine spongiform encephalopathy, and global warming. We fear that we have become too successful for our own good and that we risk destroying the natural system that sustains us. We have a sense of moral obligation to other species because caring about nature is essential for our long-term survival.