Survival of the survivors

The central lesson of biology is that survival is at the core of just about every behaviour there is, even ones that at first glance appear to increase mortality. For example, people will sacrifice themselves to save their family. If survival of the individual was the driving force, people would happily save themselves at the expense of their family. However, survival in the biological sense is defined in terms of the survival of characteristics, not individuals. Because parents share most of their behaviours with their offspring, anytime a parent sacrifices him/herself to save offspring, the parent increases the survival rate of all of his or her behaviours, whether they were passed on through genes, memes, or something else, including the one that caused the parent to make the sacrifice. If the rescuer might survive the experience, the motivation is even stronger, in inverse proportion to the risk.

Although we are more used to thinking of evolution in terms of physical characteristics, like the peacock's tail, behavioural characteristics are possibly more important. For example, on its own, the male peacock's tail would decrease its survival rate, because it's easily visible to predators, slows down the bird, and takes a lot of energy to grow and maintain. However, female peacocks choose to mate with males that survive and prosper even with massive ornamental tails. Together, the physical characteristic and the behavioural characteristic act to increase survival, by reducing the breeding rate of individuals that can't maintain an expensive tail. Without the behavioural characteristic, the physical characteristic wouldn't be useful.

This way of thinking about behaviour leads to the conclusion that ideas that have survived for a long time, e.g. the various concepts called morals, must in some way increase survival. Either that, or the theory is wrong and something else is going on.