Identifying the Explanatory Weakness of Strong Altruism: The Needle in the ‘Haystack Model’

Evolutionary theorists have encountered difficulty in explaining how altruistic behavior can evolve. I argue that these theorists have made this task more difficult than it needs to be by focusing their efforts on explaining how nature could select for a strong type of altruism that has powerful selection forces working against it. I argue that switching the focus to a weaker type of altruism renders the project of explaining how altruism can evolve significantly less difficult. I offer a model of weak altruism that can avoid many of the difficulties that evolutionary accounts of altruism have traditionally faced.