Many theists have a hard time imagining how science and evolution could explain altruism, compassion, and morality. They seem to feel these phenomena are evidence for either a god or an immaterial spirit only humans possess. Sorry to burst your bubble, but there have been many advances in our understanding of these seemingly deity-inspired emotions and behaviors.
Why would evolution lead humans, or any other animals for that matter, to perform selfless actions that would reduce the chance of an individual's survival? Well, first off, humans aren't the only species with the propensity for this behavior. Here are just a few examples from Wikipedia:
- Bonobos have been observed aiding injured or handicapped bonobos.
- Vampire bats commonly regurgitate blood to share with unlucky or sick roost mates that have been unable to find a meal, often forming a buddy system.
- Dolphins support sick or injured animals, swimming under them for hours at a time and pushing them to the surface so they can breathe.
- Vervet Monkeys give alarm calls to warn fellow monkeys of the presence of predators, even though in doing so they attract attention to themselves, increasing their personal chance of being attacked.
Science has come up with many theories regarding this sort of behavior. One of the most powerful explanations is that of Kin Selection. Given that social animals generally live in groups of genetically similar individuals, if one member sacrifices its life so that the group survives, the genes it shared with its kin will continue to live on. Thus, genes that promote helpfulness and selflessness toward one's in-group members also get passed on. It is certainly plausible that this inclination toward kindness to one's kin could lead to these behaviors being extended to out-group members as well.
Oxytocin: The Hippie Molecule (Sort of)
Oxytocin is a hormone secreted in the brain, which has traditionally been associated with promoting bonding between mother and infant during childbirth and breastfeeding. This handy molecule is primarily mammalian, but variants can be found in all vertebrate animals. So, how is it the Hippie Molecule? It not only shows up during moments of bonding, but in experiments it has been shown to promote both trusting and trustworthy behaviors. Here's the reason for the "sort of:" it has also been shown to lead to hostility toward people who are from different backgrounds. In a nutshell, oxytocin leads individuals to care for and cooperate with their own kind, while protecting each other from those who are less familiar.
Mirror Neurons and Empathy
According to Merriam-Webster, empathy is
"The action of understanding, being aware of, being sensitive to, and vicariously experiencing the feelings, thoughts, and experience of another of either the past or present without having the feelings, thoughts, and experience fully communicated in an objectively explicit manner."
Many scientists believe areas of the brain referred to as "Mirror Neurons" could be behind it. A Mirror Neuron is a neuron in the brain which fires whenever an individual performs an action or when another individual performs the same action. For example, if you find yourself wincing while watching men get hit in the crotch on "America's Funniest Home Videos," you can thank your mirror neurons. These neurons have been observed in humans, other primates, and birds, and have been linked to facilitating learning and in discerning intentionality of others' actions. Without them, Bill Clinton could never have been quoted as saying "I feel your pain," nor would we be capable of compassion.
Disgust and Morality
People generally feel disgust whenever they see others act in ways that run counter to their moral intuitions. Why would this be? Disgust is commonly a feeling one gets when encountering a festering corpse or strange foods. This is well understood in evolutionary terms, since it creates an impulse to get away from harmful pathogens. What's the connection with morality? Humans become disgusted whenever we feel that something pure has been violated. When it comes to morality, this purity generally has to do with whatever one's culture deems appropriate behavior. Disgust, therefore, appears to be a mechanism to motivate us to socially avoid or even punish those who break these social codes of conduct. The evolutionary benefit to this motivation would be to minimize behaviors that would cause the group to lose cohesion and reduce the chances of members surviving to pass on their genes. Given that disruptive individuals end up being punished or socially isolated, the probability of their survival is then reduced. This ultimately leads to more group members who are genetically predisposed to follow social rules.
One does not need to explain altruism, compassion, or morality in terms of the supernatural or even religion. Evolution has provided us with a number of adaptations that have led to behaviors and emotions which cause us to cooperate with, and care for, those within our immediate peer groups. It has also made use of our pathogen-disgust reaction to motivate us to avoid and punish those who act against the group. While our innate moral inclinations tend to be in-group focused, it is possible they provide the wiring that allows us to act morally toward those from different backgrounds.
A Great Book on the Science of Morality:
A Good Article on the Evolution of Morality:
A Good Article on Disgust and Morality:
Wikipedia on the Evolution of Morality:
A Great News Piece on the Morality of Babies: