In my blog post from 1/2/2011, Of Hormones and Ethnic Conflict, I described a biological rationale for why, under some circumstances, people are not only willing to sacrifice their own lives for their kin or ethnic group, but to sacrifice the lives of their children as well. How else to understand such diverse phenomena as mothers gladly sending off their sons to war or even to be suicide bombers, female infanticide in China, and so-called honor killings in the Middle East? The later is especially strange - fathers or brothers kill their own daughters/sisters because they have besmirched the family honor, usually through some sexual transgression - even if involuntary! Women who have been raped can suffer this fate.The mass appeal of the Jesus story, in which God sacrifices His only son in order to save mankind from the fires of hell, is probably due to this characteristic tendency of human beings. In the Old Testament, there is another widely cited story of the willingness of a parent to sacrifice a child. It is the story of God ordering Abraham to sacrifice his son Isaac as a test of his faith. He is about to do the deed when God tells him he does not have to.An interesting sidelight to this story is that in almost all artwork that depicts this incident, Isaac is portrayed as a little boy. This can be seen in the painting at the top of the post. Not so! I was surprised to recently learn that, in fact, most Biblical scholars believe, from other things in the Bible happening around the same time, that Isaac was about 37 years old!Abraham was supposedly over 100 years old at this time, so Isaac could have undoubtedly overpowered him. What this means is that Isaac must have been just as willing to be sacrificed as his father was willing to sacrifice him. Self sacrifice and the sacrifice of children often go hand-in-hand.The idea from evolutionary biology that covers this willingness, kin selection, is often criticize by many in that field due to what I believe to be a misinterpretation of the phenomenon. Indeed, it is quite true that many people are not willing to sacrifice themselves or their children at those times when most of the people within their peer group are. The willingness to follow the herd into sacrifice is an inherited biological tendency, not a mandate. Group pressure to be willing to sacrifice can indeed be very powerful - often leading resistant individuals to an almost overwhelming sense of terror known as existential groundlessnessor anomie as described in this post. This does not mean, however, that everyone simply must go along. The thinking parts of the brain can choose to ignore their fears and can override the biological tendency to follow the kin group. People who resist the herd are often in danger of being attacked or even killed themselves from others from within their group who condemn their independent ways. People may give in to these threats, but they can also stand up to them even at great peril. Where does such courage come from? That is an interesting question, and I do not think we know the answer.