Much overlooked in Darwin’s theory of natural selection is his argument for the origin of social instincts that gave rise to shared common feelings between animals in a group. For Darwin, the “moral sense” had its foundations in the pleasure an animal felt from their social community and their identification with the internal state of others, or perspective-taking. From this followed the emergent instinct to “perform various services for them,” a trait that was promoted through natural selection when groups with a high level of reciprocation “would flourish best and rear the greatest number of offspring.”

This concept subsequently formed the basis for Peter Kropotkin’s 1902 work Mutual Aid: A Factor of Evolution, first appearing as a series of articles in The Nineteenth Century beginning in 1890, and culminating in his posthumous work Ethics: Origin and Development in 1924. Both Darwin and Kropotkin emphasized that adopting the perspective of another was a natural evolutionary strategy and formed the basis for the modern conceptions of social duty and justice. 

Eric M. JOHNSON  | University of British Columbia, Canada